S0LENID.1!. 131 



SoLENOPSis, M'Coj^, 1844. 



Distr. — S. minor ^ M'Coy (cv, 85). Carboniferous ; Ireland. 



Shell like Solen, but somewhat thicker anteriorl}', and with 

 inflated beaks ; posterior end truncate. 



This genus has been proposed for the deception of some palae- 

 ozoic species, formerly described as Solen, like S. ^oelagicus and 

 vetustus of Goldfuss, S. siliquoides, Kon., and others. The gen- 

 eral form of these shells is very much like that of elongated 

 species of Sphenia ; the hinge-teeth, if any, are not as yet known, 

 and it is therefore, strictly speaking, impossible to classify the 

 genus correctly; D'Orbigny identifies it with Lyonsia. 



SoLENARiA, Stoliczka, 1S10. 



Distr. — S. affinis, Eichw. Turonian ; Russia. 



Shell thin, narrow, long and straight, like a Solen, internally 

 with two radiating, diverging ribs, originating at the beaks and 

 proceeding towards the ventral edge. The hinge is as yet 

 unknown, but the general form of the shell agrees entirely with 

 Solen. 



CuLTELLUS, Schumacher, 181 T. 



Etym. — CuUellus, a knife. 



Distr. — 12 sp. Africa, India, Nicobar, Philippines. Fossil ; 

 Tertiarj^ G. cultellus, Linn, (cvi, 10, 11). 



Shell elongated, compressed, roimded and gaping at the ends; 

 hinge-teeth 2'3 ; beaks in front of the centre, supported inter- 

 nally by an oblique rib ; pedal impression behind the umbonal 

 rib ; posterior adductor trigonal ; pallial line not prolonged 

 behind the posterior adductor ; sinus short and square. 



Animal (of C. Javanicus) with short, fringed siphons ; gills 

 narrow, half as long as the shell, transversely plaited ; palpi 

 large, angular, broadly attached ; foot large, abruptly truncated. 



ENSicuLus, H. and A. Ad. Proposed for the old Solen cultellus., 

 Linn., differing from the other species of Cultellus by its more 

 elongated, curved and parallel form, and the short, oblique ribs 

 below the umbones. 



Subfamily PHARELLIN^. 



Siphons elongated, separated for half their length. Shell 

 transverse, elongated, gaping and rounded at the extremities ; 

 umbones subcentral, instead of terminal as in Soleninse; hinge-- 

 teeth varying, usually three in one valve, two in the other ; 

 pallial impression with a profound, rounded sinus. 



Pharella, Gray, 1854. 

 Distr. — 4 sp. India, East Indies. Fossil. Cretaceous; India, 

 N. America. P. Javanica^ Lam. (ev, 86). 



