﻿236 DESCRIPTIONS OF 



Hab. — Malacca. II. Cuming. 



My cabinet and cabinet of Mr. Cuming. 

 Diam. 1, Length 1*9., Breadth 3 inches. 



Shell smooth, obovate, compressed, inequilateral, subbiangular behind ; substance 

 of the shell somewhat thick ; beaks scarcely prominent ; ligament long, rather thick 

 and dark brown ; epidermis blackish brown, darker and minutely striate on the 

 anterior portion, lighter and shining in the middle, marks of growth rather distant ; 

 umbonial slope raised and rounded ; posterior slope raised into a high carina, with 

 two raised lines passing from the beaks to the posterior margin and also with some 

 obscure small folds towards the beaks ; cardinal teeth small, with a single lobe in each 

 valve, the right one being the larger and locking in anteriorly to that in the left 

 valve ; anterior cicatrices confluent and well impressed ; posterior cicatrices confluent, 

 rather large and slightly impressed ; dorsal cicatrices well impressed and placed in 

 a row across the centre of the cavity of the beaks; cavity of the shell rather 

 shallow and rounded; cavity of the beaks, very shallow and rounded; nacre white 

 and iridescent. 



Remarks. — This is a very interesting species which I formerly described as an 

 Anodonta, but which, by examining other specimens, I am satisfied is a true Mono- 

 condyloea of D'Orbigny, although the lobed teeth are not quite so large and perfect as 

 in his South American species. It is nearly allied to Mono. Vondenbuschiana (nobis) 

 and Alas. Bonellii Fer., (which I place with the Monocondylcece) in the form of the 

 teeth, but not in the outline as regards the latter. It may be distinguished from 

 the former by its more transverse form, its carina being lower, and in having a darker 

 epidermis. In the four specimens before me the beaks are too much eroded to 

 describe the undulations of the tips, but on one there is evidence, on the posterior 

 slope, that the upper portion of the beaks may be covered with minute regular un- 

 dulations entirely to the tips. 



Anodonta subcrassa. PI. 33, fig. 115. 



Testa lsevi, oblonga, subinflata, subaequilaterali ; valvulis subcrassis, antice crassioribus ; natibus promi- 

 nentibus undulatisque ; epidermide luteo-fusca, eradiata; margarita albida vel purpurea vel salmonis 

 colore tincta et iridescente. 



Shell smooth, oblong, somewhat inflated, nearly equilateral ; valves rather thick, 

 thicker before ; beaks rather prominent and undulate at the tips ; epidermis yellowish 

 brown, without rays ; nacre whitish or purple and salmon color and iridescent. 

 Anodonta subcrassa, Lea. Proc. Zool. Soc., Lond., 1850, p. 198. 



Hab. — Laguna de Bai, Luzon, Philippines. H. Cuming. 



My cabinet and cabinet of Mr. Cuming. 

 Diam. 1*2, Length 1*7, Breadth 2-9 inches. 



