854 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. 



NUCULA CANCELLATA Jeffreys. 

 (Plates LXXXI, fig. 3; LXXXVI, fig. 5.) 



Xiicula CHHcellala VERIULL, Trans. Conn. Ac-ad., VI, pp. 231, 280, 1884; Expl. Alba- 

 tross, Report V. S. Com. Fish and Fisheries for 1883, p. 576, 1885. DALL, Bull. 

 U. S. Nat. Mus., No. 37, p. 42, 1889 ; Proc. U. S. Nat. Mus., XII, p. 258, 1889. 



A very abundant species, at forty-four stations, between N. lat. 42 

 47', W. long. 61 4', and K lat, 37 27', W. long. 73 33', in 384 to 2,033 

 fathoms, 1883-1887. South to off Tobago, West Indies, in 880 fathoms. 

 Ball. 



Family 



Subfamily LETDUSTJE. 

 LED A Schumacher, 1817. 



Leda VKRRILL and BUSH, Ainer. .Tonrn. Sci., Ill, pp. 54, (12, . January, 1897. 

 Nitciilana HARRIS, Cat. British Museum, p. 348, 1897 (not Link, 1807). 



Type. Leda rostrata (Montagu, 1808). 



This genus has been variously extended and restricted by authors, 

 and several subgeueric and sectional groups have been proposed. In 

 the more extended sense it is scarcely capable of a definition that will 

 distinguish it from Yoldia, etc. 



We proposed, therefore, to restrict it to the typical species, such as 

 L. cuspidal a Gould, L. caudata (Donovan), L. pernnla (Miiller), L. tenu- 

 isulcata (Couthouy), and many others closely related. These have a long, 

 tapered, bicarinate rostrum, and well-developed siphon tubes, partially 

 united. The palpal tentacles are long, flat, tapered, and arise external 

 to the bases of the outer palpi, which are broad with slender, acute, 

 posterior tips. 



Mr. Harris quotes rostrata Liima?us as the type of his Nuculana, but 

 no such species occurs until Gmelin's edition, 1790; rostrata Chem- 

 nitz, 1784, used by Schumacher as the type of Leda, is now considered 

 the same as flumatilis Sowerby and also Schrcet-er, 1779; rostrata 

 Lamarck, 1819, is the same as pernula Miiller, 1774 or 6?, so that in 

 using rostrata Montagu, 1808, we avoid confusion of names without 

 leading to any misunderstanding of the form of the shell, for all of the 

 above species have the same rostrated form. 



LEDA BUSHIANA Verrill. 

 (Plates LXXIX, tig. 8; LXXXII, fig. 9.) 



Leda busMana YEKRILL, Trans. Conn. Acad., VI, pp. 229,280, 1884; Expl. Alba 

 tross, Report U. S. Com. Fish and Fisheries for 1883, p. 576, 1885. DALL, Bull. 

 U. S. Nat. Mus., No. 37, p. 44, 1889. 



A few specimens, off Cape Hatteras, North Carolina, in 516 fathoms, 

 1883. South to Florida Straits, in 120 to 516 fathoms. Dall. 



1 Nuculanidw Harris, Australian Ter. Moll., Cat. British Museum, p. 348, 1897. 





