AND EXDOSKELETAL SYSTEMS OF SCOEPIO. 351 



ventral to the lateral median process, and to the arthrodial membrane between the 

 metasternite and the coxal joint of the sixth appendage. 



IV. Muscles attached to the Suprapectinal Chondrite. 



The lateral antero-posterior muscle (25) of the first segment of the mesosoma has 

 already been mentioned as being attached posteriorly to the suprapectinal chondrite 

 and anteriorly to the plastron. 



The lateral anteroposterior muscle (26) of the second segment of the mesosoma is 

 attached anteriorly to the suprapectinal chondrite. 



The dorso-suprapectinal-chondrite muscle (66) of the dorso-ventral series of muscles is 

 attached to the superior surface of the suprapectinal chondrite, as has been mentioned 

 above in speaking of the dorso-ventral muscles. 



The plastron-suprapectinal-chondrite muscle (86) has been mentioned with the 

 muscles attached to the plastron as being attached anteriorly to the plastron and poste- 

 riorly to the suprapectinal chondrite. 



The epimero-suprapectinal-chondrite muscle (87) is a small muscle attached to the 

 most lateral portion of the suprapectinal chondrite. It is also attached to the epimeron 

 lateral to the pecten. 



The posterior pectino-suprapectinal-chondrite muscle (88) is a small but broad muscle 

 which runs from the inferior portion of the suprapectinal chondrite to the posterior 

 margin of the pectine. 



The sterno-suprapectinal-chondrite muscle (89) starts from the suprapectinal chon- 

 drite, and runs to the sclerite between the pair of pectines. 



The anterior pectino-suprapectinal-chondrite muscle (90) is a small but broad muscle 

 which runs from the inferior surface of the suprapectinal chondrite to the anterior 

 margin of the pecten. 



The interior pectino-suprapectinal-chondrite muscle (91) is a small muscle attached 

 to the median part of the suprapectinal chondrite, which runs down to the interior 

 margin of the pecten. 



The exterior pectino-suprapectinal-chondrite muscle (92) is attached to the supra- 

 pectinal chondrite, and runs down to the exterior margin of the pecten. 



V. Muscles attached to the Preoral Entosclerite. (See Plate LXXIX. 

 figs. 11, 12, and 16.) 



Muscles are distributed from the preoral entosclerite to the dorsal surface, the coxal 

 entosclerite of the first appendage, and to the pharynx. There are four muscles to the 

 dorsal surface, of which one has a median attachment, the other three have lateral 

 attachments. 



The median dorso-preoral entosclerite muscle (62) is attached to the anterior part of 

 vol. xi. — part x. No. 6. — May, 1885. 3 a 



