A. E. Verrill — Study of the family Pectinidce. G5 



are mostly from the deep sea, and several are from the West Indian 

 area. I*, thalassinum (Dall) is the only species taken off our northern 

 coast, and this is not a typical species, as it has but two radial ribs,, 

 besides the auricular crurse. Dr. Dall has recoi'ded the following 

 species from the West Indian region: P. Pourtalesianum Db\\, 13 

 to 805 fath,; P. cancellatunn (Smith), 13 to 1591 fath. ; P. Hohnesii 

 Dall, 100 fath.; P. Sayanum Dall, 16 to 150 fath. He also records 

 P. Alaskensis Dall, from Alaska ; P. Hoskynsi (Forbes, non Sars, 

 nee Jeff.) from the East Atlantic and Mediterranean ; P. hicidum 

 {pars) Jeff., East Atlantic and off Brazil, 675 to 1000 fath. 



The following additional species, described as species of Amusium, 

 were obtained by the Challenger : P. scitidum (Smith), 28 fath., off 

 New Guinea ; P. Torresi (S.), 155 fath., off Cape York ; P. propin- 

 guum (S.), 100 fath., off the Azores ; P. ohliqumn (S.), 390 fath., 

 West Indies. P. thalassinum was taken in 43 and 417 fath. 



Crenipecten Hall, 1883. Type, C. crewwfote Hall ; Devonian. 



Crenij^ecten Hall, Pal. of New York, vol. v, pt. I, plates and expl., p. 3, 1883 ; sect. 

 I, Introd., p. xii, pi. ix. 



The shell and auricles are shaped much as in Euchondria, Some 

 of the species show radial sculpture. 



The hinge is said to have no median resilial pit, but to have a 

 continuous series of small transverse pits, grooves, or incisions, along 

 the whole of its length. These minute pits are probably of the same 

 nature as those of Euchondria and many modern Pectinidae, and not 

 ligament-pits. 



Several species have been described from the Chemung and Wav- 

 erly formations. 



The alleged absence of a resilial pit is the only tangible difference 

 between this and Euchondria. 



Palliolum Monterosato, 1884. Types cited: P. Testa Biv. and P. vitreum (Chem.) 

 Plate XVIII. figs. 6-14. 



This is a group separated from Pseudamusium, of H. & A. Adams, 

 and is scarcely to be distinguished from Camptonectes. 



The two species named by its author as types agree in having thin, 

 rounded, nearly equivalve, shells, with the posterior auricle poorly 

 developed, and with line camptonectes sculpture on both valves, 

 with small radial riblets, and usually with rows of small scales. The 

 margins are plain and come evenly together, without flattening. 



Trans. Conn. Acad., Vol. X. June, 1897. 



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