82 MOLLUSCA. 



close exactly, and have the lateral teeth obsolete. He de- 

 scribes seven fossil species, and eleven recent ones, viz. 

 mactra glabrata, (Encyclopedic Meth. tab. 257. fig. 3) ; ve- 

 nus divaricata of Martini, (Conch, vi. p. 318. tab. 30. fig. 

 317, 318,) under the title Crassatella contraria ; and the 

 following new species, rostrata, Kingicola (from King's Is- 

 land!) donacina, sulcata, subradiata, erycincea, cycladea, 

 and strata. 



The genus ERYCINA is composed entirely of fossil species. 

 Lamark has assigned it the following character : " Testa 

 bivalvis, equivalvis, inequilatera, transversa. Dentes car- 

 dinales bini, superne divergentes, cum foveola minima in- 

 termedia : laterales compressi oblongi. Ligamentum fove- 

 ola cardinal! insertum." From the situation of the ligament 

 being inserted in the small space between the teeth, the pit 

 or cavity is less than in any of the other genera. The mus- 

 cular impressions are two in number. 



The transverse mactrae, which gape, but are destitute of 

 lateral teeth, such as the M. lutraria of Linnaeus, compose 

 the genus LUTRARIA of Lamark. The species already men- 

 tioned, and the mya oblonga of Gmelin, or mactra hians of 

 Montagu, occur on our coasts ; the former in great abund- 

 ance at the mouths of the European rivers. 



The genus UNGULINA, formed by Daudin, contains only 

 one species, existing in the cabinet of Favanne. It is un- 

 certain from what country it came. It is a regular longi- 

 tudinal shell. The hinge is formed by one small tooth be- 

 tween two oblique pits. The muscular impressions are two 

 in number. It is figured in Deterville's edition of Buffon. 

 {Hist. Nat. des Coquil. torn. xx. f. 2, 3.) 



Another genus established by the same author, and termed 

 ERODONA, is subtransverse, irregular, and gaping, the hinge, 



