OF CONCHOLOGY. 39 



Study of the type convinces me that it differs from normal adult 

 specimens of peltoides only in being abnormally elevated, dead 

 and faded. The siphon mark is evident under a glass. The 

 epidermis is gone; and the margin is irregular, showing that its 

 station must have been unfavorable to lateral expansion, hence 

 the unusually elevated and conical form. 



The animal has not, as yet, been observed. For a littoral 

 species it has an extraordinary range ; from Monterey to the 

 Gallapagos Islands, and its discovery at the latter point by Dr. 

 Hable is extremely interesting. The only other species known 

 from Monterey and the Gallapagos are Seinele rupiuni. Shy.; 

 (J)3IodioIa capax, Conrad; ('.)BuUa Quoi/i, Gray; and i^l) Pur- 

 pura triangularis, Blainv. The three latter are doubtful. Two 

 other species of Siphonaria \_S. gigas and S. scuteUum{?)~\ are 

 reported from the Gallapagos. (The locality of S. scutellum is 

 given by Reeve as New Zealand.) 



The following species are known on the Wtist Coast, north of 

 Panama: 



Siphonaria gigas, Sby., Equador to Gulf of California. 



S. lecanium, Phil., " 



S. eharaeteristiea, Reeve {^.-gigas var.), Gallapagos and Pan- 

 ama. 



S. peltoides, Dall ex Cpr., Gallapagos to Monterey. 



*S'. scutellum, Blainv., Gallapagos. 



jS. maura, Sby., Panama. 



S. pica, Sby., Panama and Cent. Am. 



*S'. costata, Sby., " " 



S. cequilirata (Reeve), Cpr., Gulf of California. 



S. (? var.) palmata, Cpr., Mazatlan. 



S. thersites, Cpr., Puget Sound to Sitka. 



There are probably several other species on the coast and Gulf 

 of California, which I cannot determine from the material at 

 hand. There are also one or two species in Japan, which may 

 be found on some of the Aleutian Islands. 



ANISOMYON, Meek, 1860. 



Anisomyon, Meek and Hayden, Amer. Journ. Sci. and Art, 

 xxix (2d series), p. 33, pi. I {A. patelliformis), Jan., 1860. 



Type A. borealis, Morton sp. (as Hipponyx.) 



This genus was constituted for several rounded, thin, sparsely 



striated, cretaceous, patelliform shells, which have the muscular 



impression interrupted on the right side, and the apex, when 



perfect, subspiral or reflected. They appear to form a passage 



