EXDOSKELETON. ANIMALS. 17 



A. 56. Portion of a Spider (Theraphosa llondii), the carapace 

 and soft parts have been removed to show the ento^ternite, 

 in situ. 



INSECTA. 



A. 57. A section of the Hercules Beetle (Dynastes Iiemdes), 

 showing three dorsal and three ventral in-processes of the 

 cuticle that give attachments to muscles. Of the dorsal 

 processes the most anterior = prophragma, springs from 

 the anterior horder of the mesothorax ; from the posterior 

 border arises the larger mesophragma, the still larger 

 metaphragma from tho posterior horder of the metathorax. 

 These give attachment to the wing-muscles. Vent rally are 

 the antifurca, medifurca, and postfurca that serve for the 

 attachment of the muscles that move the legs. 0. C. 224. 



Hunterian. 

 Kirby and Spence, Introd. to Entomology, iii. p. 581. 



PELECYPODA. 



A. a 58. Valves of Cucullcea concamerata. A process of the shell 

 projects inwards, forwards, and downwards in the posterior 

 region of either valve to give attachment to the posterior 

 adductor. In the right valve the area of muscle attach- 

 ment is painted red. 



A. b 58. The valves of Pholas \])actylina\ dactylus. From the 

 inner surface of the shell near the umbo there is a long 

 slender process (falciform process) to the apex of which 

 the anterior retractor pedis is attached. 



GASTROPODA. 



A. 58. The two pairs of buccal fibre-cartilages of an Oriner 

 = Ear-shell (Jlaliotis tuberculata). In the upper specimen 

 they are shown detached ; in the lower in situ from the 

 left side. These cartilages lie beneath the floor of the 

 mouth, giving support to the tooth-bearing lingual ribbon 

 (radula), and attachments to the muscles that move it. 

 Wegmann, Arch, de Zool. Exp., t. ii. 1884, p. 297. 



C 



