DALL: MOLLUSCA AND BRACHIOPODA. 367 
(B. Taxoponta). 
Nuculacea. 
Nuculidae. 
Nucula Lamarck. 
Nucula Lamarck, Prodrome, 1799, p. 87; Syst. des an. s. Vert., 1801, p. 115; type, 
Arca nucleus Linné; Dall, Trans. Wagner Inst., 1898, 3, p. 671. 
Glycymeris Da Costa, Brit. Conch., 1778, p. 170, ex parte. 
Nuculana Link, Beschr. Rostock Samml., 1807, p. 155. (New name for Nucula 
Lamarck). 
Nucula tanneri Datt, n. sp. 
Shell oval, inequilateral, with low opisthocoelous beaks, brownish periostracum 
with concentric zones of darker and lighter shade; sculpture of faint concentric 
ripples giving a rude aspect to the shell; interior pearly, the margins smooth and 
entire; the chondrophore small, obliquely anteriorly directed ; anterior teeth, 
14-17, posterior, 7-9; no defined lunule or escutcheon, a faintly impressed lanceo- 
late area behind the beaks. Length, 22.5; of anterior part before the vertical of 
the beaks, 17.0; alt. 16.5; diameter, 10.0 mm. 
Straits of Magellan at station 2780, in 369 fathoms, mud, bottom temperature 
47° F. U.S. N. Mus. 96,243; stations 2781, 2783, 2784, and 2787, on the west 
coast of Patagonia, in 61 to 348 fathoms, mud, temperature 48° to 54°. 
This species, named in honor of the late commander of the “ Albatross,” differs 
from N. savatieri in its less smooth surfaces, browner color, fewer hinge teeth ; 
and slightly less ovate form, and, in proportion to its size, it is more turgid. 
In this and the other diagnoses, the anatomically anterior, usually longer end is 
designated as anterior, and the truncated end as posterior. 
Nucula savatieri MasBitte anp RocHEBRUNE. 
Plate 18, figure 11. 
Nucula savatieri Mabille et Rochebrune, Miss. du Cap Horn, Moll., 1889, p. H 112, 
pl. 8, figs. 2a—c. 
Shell pale olive, brilliantly polished, compressed subovate, very inequilateral, with 
no defined lunule or escutcheon ; posterior end short, attenuated, roundly pointed 
but hardly rostrate ; anterior slope convexly arcuate, longer, rounded in front, 
the base evenly arcuate; beaks low, slightly opisthocoelous ; hinge with twenty- 
four anterior and about ten posterior teeth; interior of the disk pearly, smooth, 
with smooth entire margins; chondrophore narrow, anteriorly obliquely directed, 
