1884.] OF THE 'CHALLENGER' EXPEDITION. 273 



upper part blackish. The expanded mantle-lappets are also spotted 

 with black. The foot is carinate above for a short distance from 

 the extremity, which is abruptly truncate, having the usual terminal 

 mucous pore. 



Parmacochlea, gen. nov. 



Animal very like that of Parmarion, but differing in the con- 

 struction of the shell. Shell almost concealed beneath the mantle, 

 flattened, oblong, having the nuclear portion in the form of a minute 

 Sigaretus-\\ke shell projecting from beneath. 



This genus appears to offer no distinction from Parmarion of 

 Fischer, excepting with regard to the shell. This takes the form of 

 a slightly convex thinnish disk, which, viewed externally, appears 

 to consist of two whorls, the nuclear one being very small, trans- 

 parent white, and shelly. The second is large, glossy, thin, covered 

 with a thin horny epidermis, marked with fine lines of growth, and 

 attached only to the left or curved side of the first whorl, the right 

 side of which is nearly straight. Beneath, the first whorl is white 

 and forms as it were a minute Sigaretus-like shell standing out free 

 from the slightly concave last volution, which is more or less tinted 

 like the exterior. 



Parmacochlea fischeri. (Plate XXIII. figs. 15-15 c.) 



In spirit this species has the general lateral aspect of Parmarion 

 extraneus as figured by Ferussac (Hist. Moll. pi. 8 F. fig. 4). The 

 mantle, however, is carried further forward over the head, the shield is 

 higher in front, the opening in the mantle through which the shell 

 is seen more central, and the truncation at the posterior extrenity is 

 inclined in the opposite direction. The foot is narrow, equally tri- 

 partite beneath, and marked along the side near the basal edge with 

 three parallel impressed lines, of which the central one is the least 

 conspicuous ; it is keeled above for a short distance from the ter- 

 minal mucous pore, is marked along the sides with divergent back- 

 ward inclined impressed lines, and is reticulately wrinkled throughout. 

 The mantle is minutely granular, with the respiratory slit a little in 

 advance of the middle. 



Length 19 millim., height 8 (in contraction); mantle 12 long. 

 Shell 7 in length, 4 wide. 



Hab. Cape York, North Australia. 



Only a single specimen of this very interesting form was obtained. 

 I have associated this species with the name of Dr. Paul Fischer, 

 the eminent malacologist of the Jardin des Plantes. 



Triboniophorus graeffei, Humbert. 



Hab. Sydney. 



The species of this genus — T. graeffei, Humbert, T. schiitJeii and 

 T. krefftii of Ke fer stein — together with Aneitia macdonaldii, Gray, 

 appear to bear externally a great resemblance one to auother. If 

 Macdonald's account of his Aneiteum slug be correct, then the 



