DEEP-WATER MOLLUSCA VERlilLL A.\l> Ill'SH. 885 



/(A. Shell lanceolate or long-ovate, posteriorly narrowed and somewhat elon- 

 gated, more or less sinuous below ; rostrum slightly defined, smooth or slightly 



carin.ite; external ligament feebly developed Yoldia (sense restrirted). 



Jilih. Shell oblong, smooth, plain, blunt and rounded at both ends, without any 



distinct earina. sinuosity or rostrum Orthoyoldia Verrill and Hush. 



Ihhh. Shell thin, compressed, narrow-lanceolate or long-elliptical, nearly (Mini- 

 lateral, and gaping at both ends; sculpture oblique. 



Adratta H. and A. Adams. 



hhhlili. Shell hyaline, oblong-ovate, broad posteriorly, concentrically sculp- 

 tured, rostrum nearly obsolete AdraneUa Verrill and Hush. 



<l<j. Shell thin, oblong, inequilateral, blunt at both ends, not rostrated nor cari- 

 u.ited; teeth few, lamellar, very oblique. Type, S. frai/ilift .Jeffreys. 



Silicula Jeffreys. 



<i((. Shell small, nearly plain, not much rostrated nor carinated ; resilium with- 

 out a prominent chondrophore, situated in a notch in the hinge-margin, inter- 

 rupting the series of teeth. 

 I. Teeth V-shaped, numerous in both series. 

 in. Shell oblong or subovate, blunt posteriorly, with a slightly sinuous margin, 



sometimes subrostrate, not carinate ToldieUn Yerrill and Hush. 



mm. Shell regularly ovate, rounded at lioth ends, not sinuous nor carinate, (?) 



no pallial sinus Sarepta A. Adams. 



//. Shell short-ovate, not sinuous nor angulated; teeth few, oblique, not regu- 

 larly V-shaped. Type, P. oralns Seguen/a Phaseolus Segueuza. 



CC. No true resilium; ligament well developed, often prominent behind the beaks 



which are usually turned forward. 



D. Siphon tubes and pallial sinus present; teeth mostly V-shaped, in two long 

 series, often interrupted by a median edentulous space. 



Mallelinw H. and A. Adams. 



o. Siphon tul>es long; pallial sinus large; shell elongated, gaping. 

 p. Shell oblong or elliptical, blunt posteriorly, not distinctly rostrate; series of 



teeth unequal; those in the anterior series fewer Mullet la Desmoulius. 



pp. Shell long-ovate or oblong, broadly angulated and sinuous posteriorly; dis- 

 tinctly rostrate and carinate; two series of teeth nearly equal. 



Neilo H. and A. Adams. 



oo. Siphon and pallial sinus small, shell ovate, not gaping; a rudimentary mar- 

 ginal resilium NeiloiieUa Dall. 



DD. Shell short-ovate or subcordate, closed at Jjoth ends, umljos prominent; liga- 

 ment entirely external; series of teeth generally continuous. 



Tiudariiur Verrill and Bush. 

 . Shell regularly ovate, grooved, without rostrum or earina; beaks turned 



forward ; no pallial sinus Tindaria Bellardi. 



ss. Shell ovate, with a distinct posterior sinuosity and a short rostrum. 



Tindariopsis Verrill and Hush. 



Family SOLEXOMY1DJE. 



SOLEMYA GRANDIS, new species. 

 (Plate LXXXV1. ligs. 1, 2.) 



Sliell large, considerably broader anteriorly than posteriorly, dorsal 

 margin in front of the beaks straight and thickened by an internal 

 ridge and a strong epidermal fold. At the anterior end the valves gape- 

 widely, and the edge of each is divided into six or seven long, nearly 

 regular, digitate processes of nearly uniform width, and obtusely 

 rounded at the ends, separated by notches, rounded proximally. The 



