133 



The habitats are only known of three of the species : S. ovalis is from Central 

 America, S. Tellinoides from California, and S. sanguinolenta from Ceylon. 



Species. 



1. ovalis, Reeve. 3. sanguinolenta, Gmel. 5. nitrea, Desk. 



2. purpurea, Desk. 4. Telliuoides, Adams. 



Figure. 



Sanguinolaria Tellinoides. PI. 38. Fig. 209. Shell of delicate trans- 

 parent rose-colour. 



Family 8. LITHOPHAGA. 



Shell; very inequilateral, irregular, more or less gaping in front ; 

 ligament external. 



The genera associated in this family are borers, and, like all borers, are 

 of very irregular growth ; they differ moreover so much at different periods 

 of their growth, that extensive series of specimens are requisite to observe 

 their specific relation. The animal resembles that of the Gastrochcena form 

 of Tubicola, in having the mantle united in front; but no tubular sheath is 

 formed, nor is it at all certain that the habit of boring is a constant habit. 

 The genera are — 



Venerupis. Petricola. Saxicava. 



Genus 1. VENERUPIS, Lamarck. 



Animal ; oblong, thick ; mantle closed in front with an opening for 

 the passage of a compressed lanceolate foot ; siphons united for 

 about half their length, their orifice fringed with a double series 

 of cirrhi, the longer ones pectinated. (Forbes.) 



Shell ; oblong, rather compressed, sculptured for the most part 

 with concentric lamina, ichich in many species are finely ser- 

 rated; hinge composed of two cardinal teeth in one valve and 

 three in the other, or with three cardinal teeth in both valves, 

 of which the central is bifid. 



Of the three genera composing the family of Lithophaga, the Venerupes 



