240 BEEMUDA. 



5. Genus Cyclas. — The shells of this. genus are 

 not larger than a hazel-nut, and some of the species 

 are verj thin and transparent, striped transversely 

 with light colours. Cyclas carnea is a familiar 

 species. 



To the fifth family of the Acephala Testacea, 

 belong the MycB, which comprise the following 

 genera : — 1. Genus Mya. These burrow in the sand, 

 and project a long tube to the surface. The species 

 most common on our shores are the Mya arenaria 

 and M. truncata. 



2. Genus Anatina.—^The shells of this genus are 

 distinguished from the Myse by their having a spoon- 

 shaped tooth in each valve, while the Myse have 

 only one. Mya globulosa is the most common species 

 found near Bermuda. 



3. Genus Solen. — The Solen, or razor-fish, has a 

 shell in the form of an elongated cylinder. A few 

 species, more especially the Solen endis, are found on 

 our shores. 



4. Genus Teredo. — The Teredines do much injury 

 to the timbers of ships, perforating them in all 

 directions, and rendering them unserviceable. Teredo 

 navalis is a very familiar example of the genus. 



11. Second Order of the Acephala: Shell-less 

 Acephales {A. nudd). — The animals of this order. 



