92 CLASS I. TROPIOPODA. ORDER I. BIMUSCULOSA. 



Deshayes and De Blainville still fail to acknowledge some of the genera 

 that Lamarck thought it necessary to institute, it cannot be denied but 

 that a free subdivision of so extensive a series is advantageous, where 

 it can be effected with tolerable accuracy. We have therefore adopted 

 the Veneres of Lamarck, with the exception of certain species removed by 

 Sowerby, to form, together with the Lamarckian Venerupes, his new genus 

 Pullastra (vide p. 95); thus we include only such as are characterized by 

 having a suborbicular globose shell, with generally three divergent car- 

 dinal teeth in each valve. 



The shell of Venus is described as being equivalve, inequilateral, 

 nearly orbicular, subglobose, generally rough on the outside, and every- 

 where closely shut. There are mostly three cardinal teeth in each valve, 

 sometimes contiguous, diverging from the umbo. The muscular impres- 

 sion of the mantle has a moderate sinus, and the ligament is external. 



Examples. 



PI. LXVII. Fig. 1. 



Venus puerpera, Linnaeus, Mantissa, p. 545. Lamarck, Anim. sans 



vert., new edit., vol. vi. p. 333. 

 Venus reticulata, var., Dillwvn. 



PI. LXVII. Fig. 2. 

 Venus subrugosa, Sowerby, Genera of Shells, No. 41. 



PI. LXVII. Fig. 3. 

 Venus thiara, Dillwyn, Catalogue, vol. i. p. 162. Lamarck, Anim. sans 

 vert., new edit., vol. vi. p. 372. Enc. Meth., pi. 275. f. 4. 



PI. LXVIII. Fig. 1. 



Venus paphia, Linnaeus, Syst. Nat., p. 1129. Lamarck, Anim. sans 

 vert., new edit., vol. vi. p. 371 . Enc. Meth., pi. 275. f. 5. 



PI. LXVIII. Fig. 2. 

 Venus cancellata, Linnaeus, Syst. Nat., edit. 12. p. 1130. Lamarck, 



