ACEPHALA TESTACEA. 415 



Some again are lenticular, where, instead of a plica, there is fre- 

 quently nothing but a slight deviation of the transverse striae(l). 



We might separate certain oblong species which have no lateral 



teeth(2), and others, which, with the hinge of the Tellinae, have not 



the plica of the posterior extremity they are the Tellinides, 



Lam.(3) 



It is necessary to distinguish from the Tellinae, the 



LoRIPES, Poli, 



In which the middle teeth of the lenticular shell are almost effaced, 

 and where there is a simple sulcus for the ligament behind the nates. 

 The animal is furnished with a short double tube, and its foot is pro- 

 longed into a kind of cylindrical cord. Besides the usual impres- 

 sions, we may observe, on the inside of the shell, a line running ob- 

 liquely from the print of the anterior muscle, which is very long, 

 towards the nates. There is no flexure in the print of the mantle for 

 the retractor muscle of the tube(4). 



LuciNA, Briig. 



Separated lateral teeth, as in the Cardia, Cyclades, &c., that pene- 

 trate between the plates of the other valve; in the middle are two 

 teeth, frequently, but slightly apparent. The shell is orbicular, and 

 without any impression of the retractor muscle of the tube; that of 

 the anterior constrictor, however, is very long. Possessing similar 

 traits of character with the Loripedes, their animals must be analo- 



gous(5). 



The living species are much less numerous than those that 



are fossil; the latter are very common in the environs of Paris(6). 



We should approximate to the Lucinae, the Unguhn^, which also 



have an orbicular shell and two cardinal teeth; the lateral ones, how- 



(1) These are the three divisions of Gmelin, but we must abstract from his genus 

 Tellina: 1st. Tell. Knorrii, which is a polished Capsa; 2d. Tell, inxquivalvis, 

 which is the genus Pandora,- 3d. Tell, cornea; T. lacustris,- T. amnica; T. Jiumi- 

 nalis; T. fluminea; T. Jluviatilis, which are Cyclades or Cyrense. 



(2) Tell, hyalitia, Chemn., VI, xi, 99i Tell- vitrea, lb., 101. 



(3) Tellinides timorensis. Lam. 



(4) Tellina lactea. 



(5) Venus pennsylvanica, Chemn., VII, xxxvii, 394 396, xxxix, 408, 409; V. 

 edentula, Id., xl, 427, 429. 



(6) lAicina saxorum. Lam., Deshayes, Coq. Foss. des Env. de Paris, I, pi. xv, 

 f. 5, 6; Luc. grata, Defr.; Ibid. pi. xvi, f. 5, 6; Luc. concentrica. Lam., Desh., 

 lb., xvi, f 11, 12. 



