32C) PHOLAMNiE. 



the valves of the shell, is filled up by a long, unsymmetrical 

 plate held in its place by a membrane. 



Species of Dactylina. 



Campechensis, Gmel. orientalis, Gmel. 



dactylus, Linn. 



Genus BARNEA, Kisso. 



Siphons naked at the base, the orifices, both branchial and 

 anal, cirrhatecl. 



Shell oblong-ovate, valves with the anterior gape always 

 open ; dorsal valve single, lanceolate ; the hinge-plate re- 

 flexed over the beaks closely applied. 



Syn. Barnia, Leach. 



Ex. B. parva, Linnaeus, pi. 89, fig. 3. Shell, B. parva, 

 fig. 3, a, 3, b. 



The single umbonal shield or accessory valve distinguishes 

 this genus from Dactylina, and the front gape being open 

 and never closed in the adult by a callous plate from Mar- 

 testa. 



Species of Barnea. 



Australasiae, Gray. fragilis, Sow. 



Bakeri, Desk. Manillensis, Phil. 



Burmanica, Phil. parva, Linn. 



Candida, Linn. similis, Gray. 

 Erythrsea, Gray. 



Genus XYLOPHAGA, Turton. 



Siphons simple at the base, slender, furnished with pec- 

 tinated ridges, and divided at the end. 



