Chatham Island, one of the Gelepagos group. Five, viz. nux, calvus, eschariferus, unifasciatus, and rugulosus, are described forms; two, to which I have applied the names chemnitzioides and achatellinus, are new, and very curious. Of these latter, the first is singularly isolated in many of its features, though bearing a resemblance sufficient to indicate an affinity with certain elongated and turreted Bulimi, natives of South America. The other is equally distinct from any known members of this genus; but, moreover, instead of linking, as the majority of the Gelepagos land-shells do, the fauna of those singular islands with the American continent, rather points, as it were, in the opposite direction, and distantly indicates affinity with the fauna of the Sandwich Isles. Unfortunately less certain as to exact locality, though contained in a box labeled "Panama," is a curious small elongated Bulimus, to which I have given the name fimbriatus. A form such as this, suggests, when we bear in mind the varied characters of its congeners, considerable doubts as to the value of the generic sections at present generally received among the Pulmoniferous Mollusca. We speak of Bulimus, Helix, Pupa, Achatina, and Balea, as if they were so many marked groups, the species in each assimilating to ideal generic types, whereas the difference between certain forms of so-called Bulimi and others placed under the same generic name is greater than between many Bulimi and Helices or Pupa. Without assenting to the views of Férussac, which would have amalgamated the genera into one, on account of the similarity in external characters of the soft parts of the animal, and fully admitting that in certain tribes the shell alone may become a most important source of generic character--in other words, granting that in certain groups the sources of generic distinction may lie in the pneumo-skeleton-I do think that we have not yet attained a natural arrangement of the Pulmoniferous Mollusks, and until we have solved that problem, we shall be seriously impeded in the study of the laws of their distribution as well as of their organization. Besides the Bulimi already named, there are specimens of Bulimus iostomus, B. Hartwegii, and a beautiful new species lately described and figured by Mr. Reeve under the name of Bulimus Kellettii, all probably from the Equador; Bulimus alternatus, from Panama; and Bulimus miltecheilus, marked from the Sandwich Islands, though this curious and beautiful shell is not known to inhabit that locality; nor have we evidence sufficient that the specimen brought home by Lieut. Wood was gathered there. Hitherto it is only known from "San Christoval, south-eastern island of Solomon's Group, northeast coast of New Holland" (Reeve), from which locality the specimens in Mr. Cuming's collection were obtained, and the single example now referred to may have possibly been brought away from the same place. Of the curious genus Achatinella, two species, livida and alba, are in the collection, both procured at the Sandwich Islands. Of Succinea there is a new species, marked from Mazatlan; I have named it Succinea cingulata. There are two species of Cyclostoma, the fine C. grande (no locality is attached to it), and an equally beautiful one which I have named C. purum. The following diagnoses of the new species in the collection have been modeled on those of Dr. L. Pfeiffer, whose admirable Monographia Heliceorum Viventium' is one of the most valuable contributions to Malacology that have been published for many years. HELIX PANDORE. H. testá obtectè perforatá, depresso-globosd, tenui, rugulosa, concentricè minutissimè striata, anfractibus supra peripheriam fuscis, infra et prope peripheriam albidis fusco cingulatá, basi albidis; aperturá rotundatá intus fusca albido-fasciatá, margine interno incrassato albo; peristomate reflexiusculo, extus albo-labiato, margine columellari dilatato, reflexo, umbilicum occultante. Diam. max. 17, min. 16, alt. 14 mill. (Pl. IX. fig. 3 a, b.) Collected near the Straits of Juan del Fuaco; allied to the last species, but very distinct. HELIX KELLETTII. H. testá angustè umbilicata, depresso-globosd, tenui, rugulosá, granulatá, fulvá, spirá subturbinatá, sordidè flavo conspersd, rufo-unifasciata, anfractibus 6, convexiusculis, ultimo ad peripheriam fasciá pallidá cincto, basi subinflato; aperturá lunato-rotundatá, intus pallide fusca, unifasciata; peristomate reflexiusculo, margine columellari dilatato, reflexo, umbilicum occultante. Diam. max. 22, min. 19, alt. 19 mill. (Pl. IX. fig. 2 a, b.) This species is nearly allied to Helix Californiensis, Lea. It differs in the more pyramidal contour of the spire, in the less tumid body-whorl, and consequently differently shaped, more lunate, slightly elongated mouth. The margin of the mouth is more reflected. HELIX VELLICATA. H. testá apertè umbilicata, tenui, convexodepressa, subnitidâ, sulcato-striata, striis minutissimis spiralibus decussatá, læte viridibus; spird convexiuscula, anfractibus 6, ultimo rotundato magno, anticè dilatato, subdescendente; aperturá perobliquá, lunato-oblongá; faux alba, peristomate margine subreflexo, supernè deflexo-sinuato. Diam. max. 22, min. 18, alt. 8 mill. From Panama? (Pl. IX. fig. 1 a, b, c.) Distinguished from its near allies by the peculiar deflexion of the upper portion of the lip-margin. BULIMUS CHEMNITZIOIDES. Bul. testá subperforata, turritosubulatá, regulariter costatá, costis numerosis, nitidulis, flavidulá, fascia spirali fusco-purpureá cinctá; anfractibus 14, ultimo longitudinis subæquante, basi fusco-purpureo; columellá subrectă, albida; peristoma simplex, acutum; margine externo supernè arcuato; aperturá ovali-oblongá. Long. 19, diam. 4 mill.; apert. 3 mill. longa, 2 lata. This beautiful species strikingly resembles a marine Chemnitzia. It is very distinct from any known Bulimus, but has affinities with B. terebralis, B. columellaris, and B. clausilioides. BULIMUS FIMBRIATUS. Bul. testá imperforatá, subuliformi, tenui, costis longitudinalibus subarcuatis, lineis confertis parallelis in interstitiis costarum sculptá, rufo-fuscá, suturá impressá; anfractus 7-8, tumidi, ultimus longitudinis vix superans, infra medium obsolete carinatus; columella subsimplex, ad basim aperturæ angulum formans; apertura subovalis; peristoma simplex. Long. 9, diam. 2 mill. ; apert. 2 mill. longa, I lata. (Pl. IX. fig. 7 a, b.) In a box of shells labeled "Panama." The nearest ally of this very curious shell is the Bulimus gracillimus of Pfeiffer, from Cuba. BULIMUS ACHATELLINUS. Bul. testá perforatá, umbilico parvo, conica, obsolete striata, nitidulá, flavidá, fusco-fasciatá; suturá cingulatá, crenulatá, albida; anfractibus 7-8 convexiusculis, ultimo vix longitudinis æquante; apertura semiovalis, peristoma rectum, simplex, acutum; columella obsoletè contorta, margine columellari reflexo, perforationem semitegente. Long. 19, diam. 10 mill.; apert. 5 mill. longa, 4 lata. (Pl. IX. fig. 5 a, b.) This shell is from Chatham Island, Gelepagos; it is unlike any other known Bulimus, and its characters distinctly indicate affinity with the Achatinellinæ. SUCCINEA CINGULATA. S. testá oblongo-ovatá, vix obliquá, soli dulá, striatá, nitidulá, fulvo-succineá, sæpe spiraliter albo-lineata; spirá exsertá, obtusá; anfractus 4, convexiusculi, ultimus longitudinis æquans; aperturd elongato-ovatá, supernè acuta, basi obliquè pone axin recedente; columellá arcuata. Long. 12, lat. 6 mill.; apert. 7 mill. longa, medio 3 lata. (Pl. IX. fig. 8 a, b.) This Succinea is distinct from any recorded by Pfeiffer. It is said to come from Mazatlan. The very fine white spiral lines are not always clearly marked in colour; they correspond with lines of deeper depression at intervals of the striæ of growth. CYCLOSTOMA PURUM. C. testá orbiculari, depressd, albá, nitidulá, spirá elevatiusculá, luteolá; anfractibus sex, rotundatis, spiraliter sulcatis, sulcis numerosis, transverse striatis; aperturd subcirculari, obliquá, peritremate simplici; umbilico maximo; operculo ? Diam. 48, alt. 17 mill. (Pl. IX. fig. 9 a, b.) Very near C. Cumingii, a species described by Mr. G. Sowerby from the island of Tumaco. 5. ON THE CHARACTERS OF THE GENERA PUSIONELLA AND CLAVATULA. BY J. E. GRAY, F.R.S. ETC. In the List of Genera of Mollusca published in the Proceedings for 1848, I gave the name of Pusionella to a genus of shell, referring to the Nefal of Adanson and the Murex pusio of Born as the type. This genus is easily characterized by the smooth thin periostraca, and the sharp-edged oblique plait which crosses the lower part of the canal. At the time I formed the genus, which contains several species in my collection, all coming from Africa, I was convinced that it was separate from the other zoophagous mollusca, from the characters assigned to it above, though I am aware that several zoologists were inclined to consider that they were scarcely sufficient for the formation of a generic group. The examination of the operculum of the shells arranged in this group has shown that it affords a most excellent character, which separates it at once from all the other genera of the family. The operculum is formed of concentric lamina, with the nucleus or firstformed lamina placed on the straight front or inner side of the operculum, which is situated next to the pillar of the shell. With this peculiarity the genus must now be regarded as firmly established. This form of operculum had only before been observed in the genus Bezoardica. The discovery of this character in shells which had been regarded by most authors as Fusi, induced me to examine the opercula of some other allied genera, and I was rewarded by the discovery that Pleurotoma bicarinata, which is very nearly allied in form to P. coronata, the type of the genus Clavatula of Lamarck's 'System,' has the operculum of the same shape and formed nearly in the same manner as that of the genus Pusionella; while Pleurotoma Babylonica, P. Virgo, and P. oxytrophis, which may be regarded as the typical Pleurotoma, have the ovate lanceolate operculum with the nucleus on the acute apex, like the typical Fusi. This being the case, it appears to me desirable that the genus Clavatula should be re-established, and restored to the species which has the operculum of this kind. Should it be considered necessary to separate from Pleurotoma the species which have a very short anterior canal, which have hitherto been regarded as Clavatulæ, they may be called Drilliæ, as that was the name which was first applied to them before they were confounded with the true Clavatulæ. These observations show the importance of studying the opercula of the different genera; and I may add, that the attention which I have been able to bestow on the subject has convinced me that they form quite as important a character for the distinction of the genera, and the arrangement of the genera into natural groups, as the structure and form of the shelly valve, or of the external form of the animals themselves; and this may well be believed, when we consider them, as I am inclined to do, as an imperfectly developed valve, and as homologous to the second valve of the bivalve shell. April 9, 1850. Prof. Owen, V.P., F.R.S., in the Chair. : The following papers were read : 1. NOTICES OF AUSTRALIAN FISH. BY SIR JOHN RICHARDSON, M.D., F.R.S. ETC. (Pisces, Pl. I. II. III.) In the third volume of the Zoological Transactions;' the 'Magazine and Annals of Natural History, vol. ix. ; a report on the "Fish of New Zealand," made to the British Association in 1842; the Ichthyology of the Voyage of the Sulphur, and especially in the Ichthyology of the Antarctic Voyage of the Erebus and Terror, completed in February 1848, I have described various species of Australian fish. Among other sources of information to which I had recourse, a collection of drawings, made by Deputy Assistant Commissary General Neill, in 1841, at King George's Sound, is particularly valuable on account of the notices it contains of the habits and qualities of the fish. The drawings are so characteristic, that most of the species are easily recognised, but some novel forms could not be systematically described without specimens, and the opportunity now afforded me by Mr. Gray of inspecting a number of dried skins prepared on the spot by Mr. Neill, has given occasion to the present paper. APISTES PANDURATUS, Richardson. Radii.-B. 7; D. 177; A. 36; C. 124; P. 14; V. 15, spec. (Pisces, Pl. I. fig. 3, 4.) Among the various forms that the genus Apistes presents, the present one is remarkable for the elevation of the orbit, which rises in a semicircular protuberance, so high above the occiput as to give the hinder part of the head a relative depression like a Turkish saddle, and to render the snout and forehead almost vertical. The mouth is terminal and small, and both jaws, with the chevron of the vomer and a round patch on each palatine bone, are furnished with minute, short villiform teeth. The intermaxillaries are moderately protractile, and the maxillary, whose dilated lower end drops below the corner of the mouth, has its posterior edge turned outwards producing a ridge. The nasal spines are thick, but acute, and are bent to the curve of the forehead. There is a narrow deep groove between them. This groove widens on the top of the head, where it is bounded by smooth ridges continued from the nasal spines, and in conjunction with them the raised edges of the orbits form an exterior furrow on each side. These four furrows and ridges end in obtuse eminences which cross from the superior-posterior angle of one orbit to the other. Behind them the skull sinks perpendicularly to the level of the nearly flat, depressed occiput, on which however the middle ridges are still visible. The preorbitar is small, very uneven, and emits a |