48 CLASS I. TROPIOPODA. ORDER I. BIMUSCULOSA. 



The genus Solenella was created by Sowerby for the introduction of a 

 new and interesting molluscura brought from Valparaiso by Mr. Cuming. 

 Its shell may be said to partake of the characters of those of Solecurtus and 

 Nucula, having an external ligament and large sinus in the muscular im- 

 pression, as in the shell of the former ; and a lateral row of sharp-pointed 

 teeth, as in that of the latter, though chiefly on the posterior side. 



He describes it as follows: "Shell longitudinally oval, equivalve, 

 nearly equilateral, compressed, shining, covered with a thin olive-green 

 epidermis ; it has no cardinal teeth, and in each valve only three or four 

 anterior lateral teeth ; the posterior lateral teeth, however, are numerous, 

 and form a nearly rectilinear series ; they are, moreover, small and sharp- 

 pointed, those of one valve exactly fitting between those of the other ; this 

 series of small teeth is placed immediately below the fulcrum, to which 

 the external elongated ligament is attached. The muscular impressions 

 are two, lateral and rather distant, and there is a large sinus in that of 

 the mantle." 



Example. 



PI. XXX. Fig. 1 to 4. 



Solenella Norrisii, Sowerby, Genera of Shells, No. 39. Sowerby, 



Proceedings Zool. Soc, 1832, p. 197. 

 Ctenoconcha (Norrisii?), Gray. 



GLAUCONOME, Gray. 



Testa oblongo-ovalis, tenuis, ventricosa, sequivalvis, inaequilateralis, an- 

 tice rotundata, postice subacuminata ; epidermide viridi tenui cornea 

 induta ; dentibus in utraque valva tribus, posticis majoribus, valva? 

 dextralis medio, sinistralis postico, bifidis. Impressiones muscula- 

 res duse in utraque valva, antica marginalis oblonga, postica sub- 

 quadrata. Impressio muscularis pallii sinu magno, antice obtuso. 

 Ligamentum externum, oblongum. 



