NO. 1139. DEEP-WATER MOLLUSC A VEREILL AND BUSH. 877 



vex, a little produced in tlie middle, and with a slight incurvature 

 toward the posterior end, below the rostrum ; the posterior end is nar- 

 rowed and produced into a short obtuse rostrum with a nearly straight 

 dorsal margin. The surface is covered with rather fine, somewhat 

 uneven, concentric lines and undulations. The hinge-margin is but 

 little thickened ; the anterior portion is the shorter and the more curved 

 and forms a very obtuse angle with the posterior portion which is 

 nearly straight. There are about twelve conspicuous, rather elevated, 

 sharp teeth in the anterior series besides three or four minute, proxi- 

 mal ones; and more than twenty in the posterior series, the number 

 being indeterminable owing to an injury to the margin close to the 

 beak. The external ligament is large and conspicuous and occupies a 

 marginal groove extending the entire length of the posterior series of 

 teeth. There appears to have been no chondrophore, but whether the 

 line of teeth was continuous is uncertain. 



Length, 14.5 mm.; height, 9 mm. 



One valve (No. 78972), station 2718, N. lat. 38 24', W. long. 71 52', 

 in 1,569 fathoms, 1886. 



NEILO Adams, 1858. 



Neilo H. and A. ADAMS, Genera of Recent Mollusca, II, p. f>l!l; III, pi. cxxvi, 

 figs. 7, la, 76, 1858. VERKILL and BUSH, Ainer. Journ. .Sri., Ill, pp. 57, 63, 

 January, 1897. 



Type. Neilo cumingii Adams. 



The type species of this genus has an oblong shell, with a straight 

 postero-dorsal margin and a well-defined rostrum, bounded beneath by 

 a pronounced furrow and a marginal indentation, while more veutrally, 

 the margin protrudes somewhat, the pouting of the margin correspond- 

 ing with special lobes of the margin of the mantle. N. cumingii from 

 New Zealand is concentrically grooved, but N. goniura (Ball) 1 from off 

 the coast of Ecuador is smooth or nearly so. 



NEILONELLA Dall, 1881. 



Saturnia SKGUENZA, Nuculidi terziurie nierid. d' Ital., R. Accad. Lincei, I, p. 1178, 



1877 (not Srhrank, 1801'). 

 Leda (section Xeilonella) DALL, Bull. Mus. Comp. Zool., IX, p. 125, 1881; XII, p. 



254, ISSG.+Salurnia Dall, p. 263. 

 NeiloneUa VEKUILL, and BUSH, Amer. Journ. Sci., Ill, pp. 57, 63, January, 1897. 



Type. NeiloneUa, corpulenta Dall. 



Shell small, swollen, short ovate, with both ends obtuse; the poste- 

 rior somewhat the longer, blunt at tip, without any distinct rostrum 

 or carina. Exterior usually concentrically grooved. Ligamental area 

 not defined. Beaks usually prominent and turned inward and slightly 

 backward. Ligament well developed, extending under and before the 

 beaks in a distinct groove, more prominent behind. Eesilium very 



1 Dall, Proc. U. S. Nat. Mus., XII, p. 251, pi. x, fig. 10, 1889. 



