110 Miscellaneous. 



visceral mass and forms in three places the wall of the stomach. 

 The latter exhibits on the right side a caecum, which appears to 

 secrete a hyaline style ; the posterior intestine runs in a ventral 

 direction and then towards the dorsal aspect ; on issuing from the 

 visceral mass it traverses the ventricle and terminates in a short 

 bell-shaped rectum. 



Kidneys greatly reduced, and situate at the posterior extremity 

 of the visceral mass, at its junction with the mantle. Renal orifices 

 behind those of the genital organs. Genital gland hermaphrodite, 

 occupying the posterior third of the visceral mass. 



The gills are the most interesting organs. On each side there 

 exists a single branchial lamella bent round into a dihedron, of 

 which the anterior ridge is occupied by a blood-vessel. One of the 

 folds is united by its margin to the mantle and the other to the 

 visceral mass, and along these lines of junction there runs a vessel 

 (or sinus) ; moreover, the two gills are united together by their tips 

 in the median line at the point where they detach themselves from 

 the body. In this way there is produced a posterior mantle-cavity, 

 communicating with the anterior one only by a median orifice 

 between the visceral mass and the point of junction of the two gills. 

 This posterior cavity is utilized as a brood-chamber, which appears 

 to be of a very different nature from that which is found in Ento- 

 valva [so far as may be judged from the very brief description of 

 Voeltzkow *]. Each branchial lamella is formed by a fold con- 

 tinuous with the mantle ; its anterior surface bears strongly ciliated 

 thickenings, resembling filaments, parallel to the cardinal margin, 

 with a haemal canal in their interior. Apertures at regular intervals, 

 in the shape of a funnel widened posteriorly, traverse tho lamella 

 between the thickenings. It seems natural to regard this organ as 

 a series of filaments fused together ; but towards the tip of the 

 gill, which appears to be in process of enlargement, we observe that 

 the lamella becomes hollowed out by apertures, and exhibits fresh 

 ciliated thickenings, while free filaments are nowhere visible. 



The pallial and visceral lamellae are united by transverse 

 trabecule. 



In a subsequent paper I shall discuss the interpretation that may 

 be attached to this gill ; I shall describe the anatomy of the 

 embryos, and shall deal with the affinities of the animal, which 

 seems to me to be allied to the Erycinids, the Galeommids, and to 

 two forms which are still insufficiently known, Chlamydoconcha, 

 Dall, and, especially, Entovalva, Voeltzkow f . Nevertheless the 

 anatomical characters are, in my opinion, sufficiently distinct to 

 justify a new generic division, and I propose for this Lamellibranch 

 the name Scioberetia australis%. — Comptes Eendus, t. exxi. no. 17 

 (October 21, 1895), pp. 569-571. 



* Voeltzkow, Entovalva mirabilis, Zool. Jahrb., Abth. f. System. &c, 

 Bd. v., 1890. 



t Dall, ' Science' (New York), vol. iv. 1885 ; see Journal de Concbyl. 

 t. xxxv. ; Voeltzkow, loc. cit. 



% This paper was prepared in the Malacological Laboratory of the 

 Museum. 





