ball: mollusca and braghiopoda. 367 



(B. Taxodonta). 



Nuculacea. 



Nuculidae. 

 Nucula Lamabck. 



Nucula Lamarck, Prodrome, 1799, p. 87 ; Syst. des an. s. Vert., 1801, p. 115 ; type, 

 Area nucleus Linne; 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. 165. (New name for Nucula 

 Lamarck). 



Nucula tanneri Dall, n. ep. 



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, 

 ll-l?, 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 27S0, in 309 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 otlier diagnoses, the anatomically anterior, usually longer end is 

 designated as anterior, and the truncated end as posterior. 



Nucula savatieri Mabille and Rochebrune. 



Plate 18, figure 11. 



Nucula savatieri Mabille et Rochebrune, Miss, du Cap Horn, Moll., 1889, p. H 112, 

 pi. 8, figs. 2a-o. 



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, sliglitly opisthocoelous ; hinge with twenty- 

 four anterior and about ten posterior teeth ; interior of the disk pearly, smoolii, 

 with smooth entire margins ; chondrophore narrow, anteriorly obliquely directed, 



