503 



1. Xylophaga globosa (pi. cviii. f. 101, 102), Soioerbij, 

 Pro. Zool. Soc, 1831. 



X. testa, globosa, in medio transverse costis duabus et area, 

 plana divisa ; parte postica subproducta, margine dorsali subde- 

 clivato ; parte antica angulatim striata, margine ventrali angulatim 

 emarginato, angulo subobtuso ; umbonibus rotundatis, laminis 

 duabus cordiformibus super marginem dorsalem reflexum posticum 

 positis. 



If there be any real difference between tins and the last species, 

 it may consist in the posterior part of the valves in X. dorsalis 

 being shorter and more elevated at the dorsal margin. The 

 opening in the ventral margin seems also to be more acute in 

 X. dorsalis. 



Found in wood at a depth of sixty fathoms at Valparaiso. 

 Cuming. 



2. Xylophaga dorsalis (pi. cviii. f. 103, 104), Turt., Brit. 

 Biv. ii. f. 4, 5. 



X. testa, globosa, in medio transverse costis duabus et area 

 plana divisa; parte postica brevi, margine dorsali subelevato ; parte 

 antica epidermide induta, angulatim striata, margine ventrali 

 angulatim emarginato, angulo subacuto ; umbonibus rotundatis, 

 laminis duabus cordiformibus super marginem dorsalem reflexum 

 positis. 



Rounded, divided in the centre of each valve by a smooth area 

 between two ridges ; the posterior part of the valves smooth, short, 

 with the dorsal margin rather raised ; the anterior part of the 

 valves covered with a brownish epidermis, and angularly striated, 

 with a large angular notch in the ventral margin. Two small 

 heart-shaped dorsal plates are placed over the umbones upon the 

 reflected anterior dorsal margin. 



Great Britain. 



3 t 2 



