Ihe Nautilus. 



Vol. XXII. MAY, 1908. No. 1. 



A REVISION OF THE SOLENOMYACID^. 



BY WM. H. DALL. 



Having recently to review the species of the Lamarckian genus 

 Solemya, and having nearly all the known species for study it was a 

 surprise to find that the group contains three well marked subgenera 

 and several subordinate sections. A full account is in preparation, 

 meanwhile the following synopsis may serve to call attention to the 

 subject : 



Genus Solemya Lamarck, 1818. 



I. Subgenus Solemya s. s. 



Ligament amphidetic, chiefly internal. Type S. australis La- 

 marck. 



Ligament appearing on the internal face of the valve in advance 

 of the chondrophore. 



A. Proximal part of the chondrophore prolonged as a thickened 

 ridge part way across the interior surface of the valve, ^. australis 

 Lam. 



B. Base of the chondrophore divided, anterior part extended as a 

 narrow ridge ; posterior part forming a thickened prop to the chon- 

 drophore ; exposed ligament linear. S. parkinsonii Gray. 



C. Chondrophore thickened, without props or extended rib. S. 

 tolen V. Salis. 



