30 MAZATLAN BIVALVES 



Smallest specimen measures long. '04, lat. '06, alt. '02, 

 Largest „ „ „ "49, '72, -24. 



Tablet 101 contains 3 yoimg valves. — 102, tlie largest (imper- 

 fect) specimen. — 103, a C. lamellosa, which had established 

 itself within the emptj- remains of a Petr. robusta, which had 

 itself gone to dwell inside the skeleton of a deceased relative 

 which had originallj- constructed the burrow.* 



The form coarctata was fouxid by Mr. Hanley in Spondylus 

 Laraarckii ; Savre Col. 



43. CUMINGIA TEIGONTTLAEIS, SoW. 



Froc. Zool. Soc. 1833, p. m.—Rve. Conch. Syst. pi. 49, f. 2.— 

 C. B. Ad. Pan. Shells, p. 288, no. 480. 



Lavignon trigoniilaris. Gray. B. M. Cat. D'Orh. Moll. j). 59, 

 no. 519. 



Tolerably well distinguished by the great proj ection of the 

 ligamental spoon and hinge teeth. The laterals are very" short, 

 truncated, and of nearly egual length. PaUial sinus ver\- large. 

 Decussating stria) well developed. N. B. The muscular scars 

 often vaiy in shape with the distortions of the shell. The 

 lai'gest specimen foimd measures long. '5, lat. '62, alt. "32. 



JIah. — St. Elena : among stones in deep water, Cuming. — 



Ecuador ; St. Elena, D'Orhigny. — Panama, very rare, C. B. 



Adams. — Mazatlan : nestling in burrows in Spondylus Lam- 



arckii ; very rare ; L'pool Sf Havre Coll. 



Tablet lt>i contains 1 perfect and 3 broken specimens, of 

 various ages. 



14. CvMiNGiA Califobnica, Conr. 



Journ. Ac. IS'at. Sc. Phil. 18 . p. 

 Teeth andpallial sinus intermediate between C lamellosa and 



C. trigouularis. Anterior side generally swollen. The largest 



specimen found measures long. "33, lat. "52, alt. "22. 



77>,/,._Upper California, iVw^^a/^.— Mazatlan ; nestling in bur- 

 rows in Spondylus Lamarckii, very rare ; L'pool Col. 

 Tablet 105 contaijis 1 young, and 2 adtJt specimens. 



* So I httTe, in limestone from Weymouth Bay, Sphacnia Binghami nestling in 

 tbe tube of a Gastroch»na modiolina which had been formed by soldering 

 together portions of a Thracia distorta through which it had burrowed. 



