MUSEUM OF COMPAKATIVE ZOOLOGY. 343 



at the base, and 3.0 mm. high. The apex is situated in the posterior fourth 

 of the length, and has a minute dextral half-immersed spiral nucleus, whose 

 extent is marked by a slight contraction where the conical shell begins. The 

 anterior slope is prettily and evenly arched, the posterior slope steep and con- 

 cave beneath the apex. The surface is of a brownish straw-color, the interior 

 subtranslucent white of brilliant polish but not nacreous. The sculpture is of 

 very numerous, fine, radiating raised lines, with minute spines or vaulted 

 scales closely set upon them, giving a rasp-like surface; there are no regular 

 concentric lines, but only occasional lines of growth. 



I have described it thus fully as I suspect Shuttleworth's name is a mere 

 catalogue name which has never been validated by a description or figure. At 

 least, after very full search I have failed to find any description or reference 

 to a description. It is not the Patella (Acmcea) antillarum of Sowerby and 

 Philippi. 



The chief characteristics of the soft parts are described under the remarks 

 relating to the genus. 



There is no relic of an epipodium, nor is there any intromittent organ in 

 the (female?) specimen examined. The margin of the mantle has a minute 

 frill or fringe of papilla?. The gill is of lamellae, exactly like that of Acmcea, 

 attached only at its base. The figure of the gill of a Polynesian species given 

 by Pease (in the Am. Journ. Conch., IV. pi. xi. fig. 26) is doubtless erroneous, 

 or rather an inaccurate rendering of an organ not observed minutely. It is 

 quite possible, as stated by Pease, that the gill may be protruded at will while 

 the animal is alive, but it would be interesting to have this observation 

 confirmed. 



The figure of Scutellina, given from a sketch by A. Adams in the Genera of 

 Recent Mollusca, is correct, but the figures are turned the opposite way from 

 the figure of the shell beside them, thus giving the impression that the animal 

 heads toward the apex ol - the shell, which is an error. The shell figured as 

 Scutellina in Sowerby's Manual, second edition, fig. 509, is a Broderipia, and 

 not a Scutellina. 



The final determination of the place which this genus should occupy is full 

 of interest, and confirms my reference of Cocculina and Addisonia to the Rhi- 

 phidoglossa. There is nothing strange in the fact that the last mentioned order 

 should have conical forms as well as spiral ones, since in other groups, such as 

 Geophila and Limnophila of the Pulmonata, we find analogous cases. The 

 importance of the facts here summarized are my excuse for including them in 

 this Report, since the species in question is not included in the Blake 

 collections. 



