52 MAZATLAN BIVALVES 



Brazils, Bio de Janeiro, Patagonia ; "Baie Blanche, Voy. 

 no. 130," jyOrbigny. Mazatlan; one specimen was sent, 

 quite fresh, papered up along with the Semeles ; L'pool Col. 

 Tablet 213 contains the specimen. 



80. MACTEA (MULINIA) ANGULATA, Gray, ms. 

 Rve. Conch. Icon. pi. ix. sp. 34. 



This species is known at once from the young of M. exoleta 

 by its stout, subtrigonal growth, the shortness of the anterior 

 portion and the rather distant umbos. The epidermis is extreme- 

 ly thin, gradually passing off towards the anterior portion, as in 

 M. exoleta; but differs in being loose, lying in irregular concen- 

 tric folds, fringed at the posterior angle. The hinge teeth are 

 large and prominent ; lateral ones very finely shagreened. 

 The muscular impressions are singularly close to the margin 

 of the shell ; pallial sinus small, oval. ? Can this be the M. 

 donaciformis of C. B. Ad. (Pan. Shells p. 293,) as the true 

 M. donaciformis is given by Rve. as from JS". Zealand.* This 

 shell seems also to have relations with M. goniata, Gray, ms. 

 (Proc. Zool. Soc. 1854, p. 70,) and with M. carinulata, Desk. 

 (Proc. Zool. Soc. 1854, p. 67 : Eve. Conch. Icon. pi. 10, sp. 38), 

 both from the gulf of California. Long. 2'25. lat. 3'05, alt. 178. 

 Hob Gulf of California, Beeve. S. W. Mexico, P. P. C.-~ 



Mazatlan ; a very few specimens were found with M. exoleta : 



L'pool Col. 



Tablet 214 contains two specimens ; one young with the 

 epidermis perfect ; the other adult. 



GENUS GNATHODOST, Gray. 



Gnathodon, Gray, Am. Journ. of Science ? 1830. Bangia, 

 Desmoul. Ac. Soc. Lin. de Bord. 1831. Clathrodon, Conr. 

 Sillim. Amer. Journ. 1833. , 



JL 81. GNATHODON (Bangia) TEIGONA, Petit. 



G. t. solidd, subtrigonali, alba, epidermide flavescente, pos- 

 terius rugosa, induta ; plus minusve incequilaterali, parte pos- 

 teriori angulo db umbonibus decurrente indistincte separata; 

 imbonibus subcentralibus, distantibus, non spiraliter recurvis ; 



* Reeve however, under M. carinulata, sp. 38, speaks of M. donacifcfrmis as 

 from the Gulf of California. ? Is it authenticated from both localities. 



