64 



PROCEEDINGS OF THE ACADEMY OF 



[Feb., 



the exact spot not noted. Two living ones measure, alt. 9.8, diam. 

 16 mm., and alt. 9.2, diam. 16 'mm. 



A bleached shell was found at Station 2; alt. 11, diam. 18 mm. 



Soft anatomy of S. optata. Specimens from four colonies have 

 been dissected. In the type lot from Station 1, the sole is pale, 

 unicolored. In some other lots the narrow side areas are a shade 

 darker. The genitalia (pi. IV. fig. 1-4, 7) are characterized by the very 

 small penis and absence of a flagellum, verified in several examples 

 opened. The lung (fig. 4, right fig.) has venation much as I have 



Fig. 4. — Pallial region of Sonorella optata, two individuals. K, kidney; P, 



pericardium. 



described for S. ashmuni. The secondary ureter is open throughout, 

 being defined by a thread-like ridge only. Length of lung 26, of 

 kidney 14, of pericardium 5 nun. The foregut and crop are deeply 

 sulcate longitudinally. 



In specimens from the cleft in Big Emigrant Canyon (No. 94,321), 

 the penis is rather larger (pi. IV, fig. 4). It has a thin, rather short 

 basal sheath and long retractor. The penis-papilla is slender, cylin- 

 dric, weakly annulate, with obtusely conic end. There is an exces- 

 sively short ccecum representing the flagellum, not free from the 

 integument and hardly visible except by transmitted light. The 



