294 ANATOMY OF THE LAMELLIBRANCHIATA. 



Section 4. Idoteides. 



Idotea, sub-genus. 



I. entomon, (Oniscus marinus, Penn.) Plentiful ; 'Ed. Enc.' vii. 404. 

 Stenosoma, sub-genus. 



S. acuminatum. " Semel obvium," Leach, ' Mem. Wern. Soc' ii. 



Section 5. Asellotes. 



Asellus, sub-genus. 



A. vulgaris, (Oniscus, Linn.) Ditches and wells; ' Diet. Sci. Nat.' v. 

 Oniscoda, sub-genus. 



O. (Janira, Leach) maculosa. Devon coast, rare; ' Mem. Wern. Soc' ii. 

 JjERa, sub-genus. 



J. albifrons. Very common ; Leach, ' Ed. En.' vii. 434. 



Section 6. Cloportides. 



Lig i a, sub-genus. 



L. oceanica, (et scopulorum). Rocks, Devon. Museum of the Plymouth 

 Institution. 

 Oniscus, sub-genus. 



O. Asellus, Wood-louse. Common. 

 Porcellio, sub-genus. 



P. Icevis. Devon, rare ; Leach, ' Edinb. Enc' vii. 406. 

 Armadillo, sub-genus. 



A. vulgaris, (Oniscus, Linn.) Roots of trees and rocks ; Leach, ' Edinb. 

 Encycl.' vii. 406. 



Plymouth, Aug. 28th, 1838. 



Art. VII. — On the Anatomy of the Lamellibranchiate Conchiferous 

 Animals. By Robert Garner, Esq., F.L.S. 



( Continued from Page 171 J. 

 EXCRETORY SYSTEM. 



The veins of the mantle are large and numerous^ and are, 

 when shown by injection, curiously and regularly disposed. 

 These veins probably furnish the calcareous matter, which 

 exudes, and forms the shell. They often contain carbonate 

 of lime, which, examined by the microscope, is seen to be in 

 the form of minute spicula. At some periods the blood con- 

 tains more of this matter than at others ; thus in the fresh- 

 water muscle anatomists have been puzzled to account for 



