OF CONCHOLOGY. 123 



(not at right angles to the septum and behind its end, as in T. 

 dorsata or cMlensis). The main processes are then deflected 

 neurally, and the extreme "bight" of the loop is straight and 

 somewhat angulated at each side. The perforations externally 

 are moderate, arranged in quincunx order, smaller and more 

 regular than in 1\ dorsata, which is its nearest analogue. 



The species appear to me to be perfectly distinct from any 

 other described Terehratella. 



The other recent species are : 



Terehratella frontalis, Midd. Malac. Rossica, iii, p. 2. Sib., 

 Reise. Bd. ii, p. 241, pi. xviii, fig. 9, 10, II, 12, 13 and 14. 

 Hah. South coast of the Ochotsk. 



Terehratella rubella, Sby., Thes. Con. v, i, p. 350, pi. 69, f. 

 40, 41, 42. Hah. Japan. 



Some little confusion attaches to this species on account of its 

 outward similarity to Waldheimia picta, Chemn. sp. from Java 

 and Ismenia sanguinea, Chemn. sp. (+ sanguinolenta, Cm., + 

 erythroleuca, Quoy, + pulchella, Sby.,) from the Philippines and 

 the Sandwich Islands. 



Terehratella Bouchardii, Dav., P. Z. S. 1852, p. 77, pi. xiv, 

 fig. 4 to 6. Hah. f This species somewhat resembles T. fron- 

 talis, which in Middendorf's figures seems to have lost the delti- 

 dia. 



Terehratella Lahradorensis, Sby., Thes. Conch, vii, p. 362, pi. 

 71, fig. 89, 90. Hah. Coast of Labrador. 



Terehratella Marice, A, Ad., An. Nat. Hist. 1860, p. 412. 

 Hah. Japan. 



Subgenus Laqueus, Dall, 



Shell with the reflected portion of the loop attached by slen- 

 der processes, on each side, to the haemal processes, at or near 

 the points where the two septal processes branch off to the 

 septum. Foramen complete. 



It will be observed that the reflected part of the loop is 

 attached by the two (lateral) processes, not to the septum nor 

 to the septal processes, but to the haemal portions of the loop, 

 (which I have termed haemal processess) ; thus the two septal 

 processes, the two lateral processes, and the "bight" of the 

 neural loop, form a somewhat sinuous ring, intersected by the 

 point of the septum, the haemal processes and the two sides 

 of the neural loop. 



Type. Laqueus californiciis, Koch sp. Plate 7, fig. f, pi. 8, 



fig. 9, 10. 

 Terehratula californica, Koch, Kuster, Nov. Ed. Martini, viii, 



