MOLLUSKS. 45 



softened iu water only — had the plates so much affected by the decorti- 

 cation of the whole jugular portion tbat I was unable to extract them 

 in a perfect condition. However, all the characters could be made out 

 except the niucro, which, judging by the remaining strise of growth, 

 must have been central, or nearly so. (Carpenter MS.) 



HELICID^. : 



Helix (Hyalina) hookeki. 



Eelix hooJceri, Pfr. Mon. Hel. iii, 88, No. 531. 

 Selix hoolceri, Eeeve, Conch. Icon. 208, n. 1474. 

 Mus. No. 11901. 



Kergueleu Island, Hooker, Dr. Kidder. Gregarious about and under 

 stones. Occasionally the shell of this species ajjpears to be partly mem- 

 branous, aud in drying, from this cause, the spire is frequently abnor- 

 mally flattened. 



SIPHONAEIID^. 



SIPHONARIA TKISTENSIS. 

 Siphonaria tristensis, Sby. Gen. Sh. f. 3. ; Dall. Am. .Tourn. Conch, vi, 1870. 

 Six>honaria lessoni, Blainv. teste'Rxe. Ic. v., fig. 23, a, 6. 



Mus. No. 11905. 



Tristan d'Acunha, Eve. Orange Harbor, Patagonia, United States 

 Exploring Expedition; Kerguelen, Dr. Kidder; abundant between tide- 

 marks. 



ACEPHALA. 

 LASEID^. 



Lasea rubra, Mont. 

 Mus. No. 11906. 



Kerguelen Island, Dr. Kidder, four specimens ; with mussels. Dis- 

 tribution world-wide; These individuals are rather larger than most 

 northern specimens. 



EEPTONID^. 



Lepton parasiticus, n. s. 

 Mus. No. 11907. 



Shell small, elongate ovate, inflated, thin ; beaks nearly central, not 

 prominent, surface shining, but not polished, with the texture of a Pan- 

 dora. Shell white, hardly sculptured, but under a high magnifying 



