REPOKT ON THE GASTEROPODA. 119 



embryonic, and are very finely, microscopically, reticulately scratched. Whorls 4, of not very 

 rapid increase, convex above, rounded at the periphery, and a little excavated on the base 

 by the large-mouthed umbilicus. Mouth large, very oblique, and round, but a considerable 

 section of the circle is cut off by the irregular and twisted pdlar. Outer Up descending, 

 well arched all round ; beyond the point of the pillar it sweeps on with a sharp, prominent 

 edge, enclosing the umbilicus, up into which it plunges direct. Inner Up strong and 

 defined, but excessively short and retiring on the body, being cut quite away so as com- 

 pletely to expose the umbilicus, deeply but widely sinuated at the top of the pillar, which 

 is slightly twisted, has an oblique, sharp, rounded, but not at all patulous edge; is bluntly 

 toothed, and slightly truncate at the point, which does not run out to the edge of the 

 outer lip, but dies out gradually just within it. Puncture consists of a single most minute 

 oval pore, which opens in a slight bulge of the exterior a little way back from the lip- 

 edge, and has a very slightly thickened margin inside ; from it a slight straight furrow 

 runs forwards along the inner surface of the shell ; the surface longitudinals bend sharply 

 backwards at the hole, and a little way before the opening is reached, as if preparation 

 were being made for the formation of the opening before it was accomplished. L. 0"053 in. 

 B. 0-078. Mouth, length 0-043, breadth 0-044. 



The peculiarity of the outer lip in its relation to the umbilicus in this and the preceding species, 

 a feature which often occurs also in the fossil genus (Trochotoma), will probably offer a sub-generic, 

 or even generic distinction, for those who love to multiply our difficulties of nomenclature. 



3. Schismope carinata, n. sp. (PI. VIII. fig. 6). 



April 23, 1874. Port Jackson, Sydney, Australia. 6-15 fathoms. 



Station 185b. August 31, 1874. Lat. 11° 38' 15" S., long. 143° 59' 38" E. Eaine 

 Island, Cape York, North-Eastern Australia. 155 fathoms. Coral sand. 



Shell. — Tumid, but depressed, finely ribbed and strongly keeled, with a flattened but 

 scalar spire, convex whorls, a minute apex, a tumid base, and a large funnel-shaped, 

 shallow, carinated umbilicus. Sculpture: there are both above and below sharp, little, 

 distant, curved, radiating riblets, between which the whole surface is exquisitely scratched 

 with microscopic lines. Spirals : there is a strong, rounded, expressed double keel, formed 

 by the two edges of the canal scar, which encircles rather more than the whole of the last 

 whorl (except near the mouth) ; this canal is sunken and is strongly scored. Above the 

 canal the surface is smooth, but a few microscopic spiral threads exist ; below and remote 

 from this canal there are on the base three, strong, round to square threads, of which the 

 highest is the strongest, and tends to become flattened and expanded into a great spiral fold 

 of the shell rather than a mere thread ; besides these another similar but weaker encircles 

 the umbilicus. Colour hyaline, but. hardly glossy. Spire slightly exserted, the whorls 



