^°i'8i)x'''] PROCEEDINGS OF THE NATIONAL MUSEUM. 343 



Tlie iigures recently given by Mr. Biiiuey in liis tliird SH[)i)leiMent to 

 the fifth volume of the Air-Breathing Mollusks of the United States 

 are not new drawings from the original specimens which furnished a 

 basis for the brief and purtial descrii)tion of O. (■arpenteri., as lirsti)ub- 

 b'shcd by him in the Proc. Acad. Nat. Seieiujes of Philadelphia, but 

 from a specimen sent to him by Mr. Dall, one of the Fisher lot de- 

 scribed by me in 1S78, and, as I now regard it, erroneously referred to 

 his species. His (>. Carpenicri is ;i much smaller form, "the length 

 of the largest* being 5 millnneters, the extreme breadth 3 millimeters," 

 while the Fisher spec'imens average 17.2 in length by 12.2 millimeters 

 in breadth. 



My former description is here given with some modifications. Body 

 oblong ovate, about a third longer than wide; convex or rounded above, 

 fiat <m the under side; anterior and posterior ends equally rounded; 

 dorsum formed by the mantle and entirely covering the T)ack, which 

 is of a smoky-biown color, coriaceous and ((uite thick at the edges; 

 under side of a dingy, yi^llowish color. Surface of dorsum covered 

 with wartlike i)apilhe, some larger than others, the larger having 

 somewhat the aspect of regularity, the intervspaces being filled with 

 the smaller; cree])ing disk or belly, elongated, nearly as long as the 

 animal, and its width equal to ab<mt one-third of the entire width as 

 seen from the under side. 



Sexual organs on the right side, near the head. Resjiiratory orifice 

 on the left side, between the edge of the creeping disk and the mantle, 

 at a- i)oint about two-fifths of the total length from the j)osterior end. 

 Anal outlet on the right side, very near flie posterior extremity of and 

 just above the edge of the creeping disk. The eye peduncles rather 

 short, and these as well as the buccal appendages are obscured by the 

 contraction caused by the alcohol. The creeping disk being compara- 

 tively soft is much contracted by the same cause. Mr. Fisher remarked 

 that he lound this form "abundant, attached to the under side of stones 

 at low tide, sometimes overlai)ping each other." 



In Ilutton's Catalogue of the Marine Mollusca of New Zealand, 

 he includes a species, Onchidella nifjrieans Quoy, "uniform black, * 

 * * connnon on rocks between tide marks," having the same habit 

 in this lespect as O. Binneyi. 



The localities wlnne Mr. Fisher collected his s]>ecimens are in the 

 Gulf of California, on the westerly shore, the fiist in latitude 28° 2G', 

 the secoml in 28° 50', and the third and last in latitude 29 north, as it 

 will be observed, not fiir from each other. Onchldium Carpenten Bin- 

 ney is credited l)y the author as ranging geographically from the 

 "Strait of Fuca to the Gulf of California." It is probably a distinct 

 species and will sooner or later be verified by additional specimens in 

 a suitable condition to admit of its characters being definitely ascer- 

 tained and described. 



Bimiey's Manual, p. 163. 



