240 



Long. 3Y4, lat. i'/^; apert. alt. 17. Mill. 



This species has some resemblance with the preceding one, but is much more slender, 

 it is not the juvenile state, for it should never reach the breadth of that species, if it proved 

 to be the male, this would be an extraordinary case of dimorphism in Mollusca; only the 

 circumstance that it has been found on the same animal, is a reason to be cautious. J\hicronalia 

 oxytenes Melv. (Proc. Mai. Soc. Lond. VI, p. 163, fig. 13) is also a species, similar by its size 

 and shape, but with cylindrical whorls. 



6. Mucronalia varicosa Schepman. PL XVII, fig. 2. 



ScHEPMAN, in Schepman & Nierstrasz. Parasit. Prosobranch. d. Siboga-Expedition, Leiden, 

 1909, p. 4. 



Stat. 164. i°42'.5 S., I30°47'.5 E. Near New Guinea. 32 M. 2 Spec, on AstrocJialcis tubercn- 

 losiis Koehler, i loosened one and 4 specimens without exact locality, perhaps 

 from the same station. 



Shell small, oval, imperforate, white, rather smooth, with very fine growth-striae and a few 

 riblike varices on the last whorl. Whorls about 6, of which the two apical ones are mucronate, 

 the other whorls are convex with a deep marginate suture. Aperture subovate, its upper angle 

 moderately acute, right margin thin, slightly expanded, regularly flexuous, stronger so near the 

 upper part, columellar side slightly arched, a little thickened near the base, with a thin layer 

 of enamel on the bodywhorl. Operculum thin, horny. 



Long. 4, lat. 2Y3 to 2'^j^-, apert. alt. 2^.1, Mill. 



The species varies slightly in shape, some specimens being more swollen than others, 

 which may depend on sex; the varixlike striae on the last whorl are remarkable, they remind 

 those of Stilifer variciferus Hedley (Mem. Austral. Museum, Vol. Ill, p. 411, fig. 5), but that 

 is guite another shell, belonging to the section of exa^'atus. These varices probably result of 

 former margins, which by being expanded, caused these riblike processes. 



After this description was written I found a fine specimen from Stat. 164, amongst the 

 Eulimidae, but this was loosened and consequently not immediately recognized as a parasite. 

 Its length is 5^3 Mill, and it has the varices very well developed. 



Stilifer Broderip. 



The description of the soft parts or animal of Stilifer are rather different from each 

 other; if one compares the description of Stilifer Tiirtoni Brod. by Jeffreys (British Concho- 

 logy, Vol. IV, p. 195) and his figures of the animal (I.e. PI. 3, fig. 2), with that of Stilifer 

 celebensis Klikenthal (Abh. Senckenb. Gesellsch. Band 24, 1898, p. 6, PL i, fig. 6; PL 3, fig. 16) 

 one would scarcely think that the authors deal with the same genus. 



I. Stilifer sp. 



Schepman, in Schepman & Nierstrasz. Parasit. Prosobranch. d. Siboga-Expedition, Leiden, 

 1909, p. 5. 



Stat. 300. io°48'.6S., 123° 23'.! E. Timor Sea. 918 M. 2 Spec, on Aspidodiadema tonsnm Agass. 



