726 



DEEP WATER MOLLUSKS AND BBACHIOPODS—DALL. vol.xvii. 



had described under the specific name of jeffreysi is the ismeniiform 

 stage of the shell afterwards named vancouvericnsis. 



The fact that specimens of Terehrotalia transversa become more red- 

 dish and bright colored when living in the southern part of their range, 

 and the stunted size of the first adult specimens of jeffreysi collected 

 in the north, led me to regard them as belonging to a northern race of 

 the ruddier califvrnicus; but since specimens of jeffreysi from the 

 vicinity of San Luis Obispo show no tendency to take on ruddy tints 

 and preserve the characters of the northern specimens, though attain- 

 ing an equal or even greater size than caUfornicus^ it is evident that 

 the expected transition does not take place, and the form may jDroperly 

 be separated as a species (though nearly related to californicus) under 

 the first name by which it was described and figured. Before the 

 development of the loop in Terehratellidw was fully understood, tlie 

 similarity of certain specimens of the ismeniiform stage of Dallina sep- 

 tigera. to those of L. jeffreysi led me to question whether the latter might 

 not be common to the two oceans, but later when the various stages 

 through which B. septigera passes became better known this suggestion 

 was obviously not required to explain the presence of the supposed 

 Frenula in the Atlantic Ocean. 



The genus, or subgenus, Laqueus appears to be strictly confined to 

 the shores of the north Pacific, where the following species occur: 



Laqueus pictiis, Chemnitz. 

 Laqueus hJanfordi, Duuker. 

 Laqueus ruhellus, Sowerby. 



NORTHWEST AMERICA. 



Laqueus jefrei/si, Dall. 

 Laqueus califoruiciis, Koch. 



Genus T E RE B E AT AL I A, Beecher. 



TEREBE ATALIA OBSOLETA, D a 1 1 . 



Plate XXX, tig. 7. 



Terehratella occidcntalis var. ohsoleta, Dall, Proc. U. S. Nat. Mus., xiv, 1891, p. 



186. 

 Terel)rataUa ohsoleta, Dall, in Beecher, Dev. T. ohsoleta, Trans. Conn. Acad, ix, 



p. 392, 1893; type of genus. 



Stations 2983 and 2984, in 58 and 113 fathoms, sand, northwest from 

 Cerros Island, Lower California, and 3044 in 58 fathoms off Abreojos 

 Island, Lower California; bottom temperatures, 50° to 56° F. E"os. 

 122545, 123140-'43, U.S.N.M. - i ' \ 



Shell scarlet, radiately streaked with pale yellow, especially in the 

 channels between the ribs ; surface polished, smooth except for rather 

 distinct incremental lines and, in adult specimens more or less dis- 

 tinct, partially obsolete radial ribs, which appear near the margin, but 

 do not extend to the earlier half of the shell; in senile specimens a 

 larger proportion of the shell is ribbed; pedicle valve with a rather 

 low beak and wide, incomplete foramen; deltidial plates well developed 

 but widely separated; valve wider (as a rule) below the middle, the 



J] 



