NO. 9 MUSCULATURE OF THE BLUE CRAB COCHRAN 21 



encircles it and holds it near to the mandible. Both remotor muscles 

 oppose the promotor by lowering the coxopodite. 



57. Musculus adductor anterior coxopoditis I maxillae (fig. 7). — 

 This exceedingly long and slender muscle arises on the epibranchial 

 region of the head carapace and is inserted without a tendon on the 

 anterior margin of the base of the coxopodite near its mesal end. It 

 brings the free end of the coxopodite toward the mouth. 



5^. Musculus adductor posterior coxopoditis I maxillae (fig. 7). — 

 This very slender, long muscle originates on the head carapace with 

 the preceding and is indistinguishable from it at first ; it travels for- 

 ward, inward and ventrally to its insertion on the posterior margin of 

 the base of the coxopodite, which it pulls forward and inward. 



5J. Musculus abductor coxopoditis I maxillae (fig. 7). — Arising 

 on the head carapace at the origin of the preceding two and at first 

 indistinguishable from them, this muscle, likewise very slender, is at- 

 tached dorsally to the extreme outer border of the coxopodite on the 

 same disk-shaped ossification that gives attachment to the promotor. 

 It opposes the adductor in pulling the coxopodite away from the 

 midline. 



^4. Musculus levator I maxillae (fig. 7). — This muscle arises 

 on the anterior part of the head apodeme, just median to the promotor, 

 traveling forward to the dorsal median proximal border of the inner 

 half of the coxopodite, which it raises. 



^^. Musculus depressor I maxillae (fig. 7). — Arising on the ventral 

 surface of the head apodeme under and slightly posterior to the origin 

 of the levator, this muscle continues forward directly under the levator 

 to its insertion on the ventral proximal border of the inner half of the 

 coxopodite, which it pulls downward. 



^6. Musculus adductor endopoditis I maxillae (fig. 7). — This 

 muscle arises on the inner proximal border of the inner half of the 

 coxopodite and branches into a fanlike formation at its manifold inser- 

 tion in the central part of the endopodite, which it brings toward the 

 center of the body. The basipodite is no longer distinguishable as such 

 in this appendage, and its position is postulated only by the presence of 

 the endopodite, which when present always arises from the basipodite. 



THE SECOND MAXILLA 



Although this appendage has the most complex system of muscles 

 of any in the blue crab, yet its muscles correspond more closely to 

 those in Astacus and in Pandalus than do the muscles of its other 

 appendages. The muscles leading to the parts bordering the mouth are 



