FAMILY 7. NYMPHACEA. 79 



TELLINA, Linnaeus. 



Testa transversa vel orbicularis, subaequivalvis, insequilateralis, planulata, 

 latere antico subrostrato, angulato, margine ventrali plerumque irre- 

 gulariter rlexuoso ; dentibus in utraque valva cardinalibus plerumque 

 duobus, lateralibus duobus, sa?pe remotis, interdum nullis. Impres- 

 sio muscularis pallii sinu maximo. 



The genera Tellina and Tellinides of Lamarck are here united in ac- 

 cordance with the opinions of De Blainville and Deshayes, who clearly 

 demonstrate that the distinguishing characters which Lamarck and Sow- 

 erby have assigned to the shell of the latter, namely, the absence of the 

 irregular flexuosity on the anterior ventral margin, and also of the lateral 

 teeth, are but an inconstant variety of growth. 



We have therefore described the shell of Tellina as being transverse or 

 orbicular, nearly equivalve, flat, with the anterior side somewhat beaked 

 or angular, and generally irregularly flexuose at the ventral margin. 



There are two lateral and two cardinal teeth in each valve ; the former, 

 however, are often remote, and sometimes altogether wanting. The mus- 

 cular impression of the mantle has a very large sinus. 



Examples. 



PI. LV. Fig. I . 



Tellina opercularis, Sowerby, Genera of Shells, No. 31. 

 Tellina operculata, Gmelin. 

 Tellina rufescens, Chemnitz. 



PL LV. Fig. 2. 



Tellina scobinata, Linnaeus, Syst. Nat., p. 1119. Lamarck, Anim. 

 sans vert., new edit., vol. vi. p. 201. Enc. Meth., pi. 291. f. 4. 



