82 MAZATLAN BIVALVES 



.L 115. PClfiCE SUBTBIGONA, *?. S. 



C. t. parvd, subtrigond, po slice longius, margine ventrali 

 ovali ; concentrice tenui ssime striatd; umbonibus ap- 

 pressis, subrugosis ; ligamento celato ; dentibus lateralibus 

 posticis magnis, anticis subapproximatis ; impressionibus 

 muscularibus d margine distantibus ; albo-lutescente, macula, 

 fu sea post ice, intus subrugosa, et lineis divaricatis hue et 

 illuc pictd ; epidermide tenui. 



Known at once from C. raargarita by its shape which is 

 longest behind ; by the very fine concentric strise ; the large 

 posterior tooth (not so large however proportionally as the 

 anterior tooth of C. margarita ;) and the painting, which dis- 

 plays a large irregular brown patch inside, which projects 

 somewhat above the regular level and is slightly rugose, and a 

 few irregular zigzag lines on a yellowish white ground. I have 

 not been able to trace the pallial line. There is no trace of 

 sinus, though the colour markings sometimes give an erroneous 

 appearance of it. In other respects the generic characters are 

 satisfactorily marked. It is somewhat less uncommon than 

 C. margarita, though I found very few fresh specimens. This 

 greatly exceeds it in size. Long. '08, lat. ' 11, alt. *04 



Hob. Mazatlan ; on Spondylus Lamarckii, rare ; L'pool Col. 



Tablet 413 contains 2 minute valves, cardinal teeth not 

 formed ; 2 adolescent and a pair united ; and 2 valves adult. 



GENUS GOULDIA, C. B. Adams. 



As I have neither had the good fortune to find the original 

 diagnosis of this genus, nor to meet with any conchologist who 

 understood it, I can only guess what it was meant to include. 

 The late learned and very accurate Prof. Adams, in his descrip- 

 tion of the following species, gives no account of the teeth. 

 Fortunately however Mr. Cuming possesses and has allowed me 

 to examine type specimens of G-. parva and Pacifica, received 

 from the Professor. The former bears a general resemblance 

 to our ? Circe minima : the second is undoubtedly the Mazatlan 

 shell, and is like an Astarte with lateral teeth, such as occur in 

 not a few of the Crag species. A third species is now added, 

 from its general agreement with the second. 



