86 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 20 



Botula fusca (Gmelin) 1791 



PI. 9, fig. 52 ; text figs. 70-72 



Mytilus fuscus Gmelin, Systema Naturae, ed. 12, 1791, p. 3359. 

 Syn.: Mytilus cinnamominus Chemnitz 1785. 



Modiola cinnamomea ouct. non Lamarck 1819. 

 Holotype: ? 

 Type loc: ? 



Remarks: This species, which has been given the name of the West In- 

 dian species, was reported by Carpenter (1856) from Mazatlan as 

 Lithophagus cinnamomeus (Chemnitz) and by Strong and Hanna 

 (1930) from Las Tres Marias as Botula cinnamojiieus (Chemnitz). 

 As far as is known, these are the only records of Botula from the west 

 coast of America. 

 Distribution: Mexico. Atlantic: North Carolina to the West Indies. 



Genus DACRYDIUM Torell 1859 



Dacrydium Torell, Bidrag till Spitsbergens Molluskfauna, 1859, p. 138. 

 Type of genus: f Mytilus vitrea Holboll in Moller 1842. 

 Remarks: This genus, erected for the small deep water species from the 

 northern Atlantic, comprises species both from the Arctic and the Antarc- 

 tic regions. One species, Dacrydium pacificuin, is reported by Dall ( 1916) 

 from the Bering Sea, in 1401 fms. This is the only report hitherto from 

 the west coast of America. 



The species of Dacrydium are all small, white, hyaline shells, with 

 anterior umbones, internal resilium, and crenulated anterior margins. 

 The type of the genus has also a thickened support for the anterior ad- 

 ductor. The new species described here seems to have to be placed in the 

 genus Quendreda, which is supposed to be of subgeneric rank. 



Subgenus QUENDREDA Iredale 1936 



Quendreda Iredale, Rec. Austral. Mus., vol. 19, 1936, p. 271. 

 Type of subgenus: Dacrydium fabale Hedley 1904 (orig. ). 

 Remarks: As is usual with generic names proposed by Iredale, there is 

 no diagnosis. He states only that the species described by Hanley "diflFers 

 in shape, form, and sculpture from the Spitzbergen shell, the type of 

 Torell's genus." Hedley (1904), in the description of fabale, says: 

 ". . . delicate, concentric growth-lines which rise into ridges on the 

 ventral side. Hinge: a deep chondrophore, flanked by two prominent 

 grooved cardinals." The two grooved teeth and the lack of a thickened 



