MOEPHOLOGY OF CYCLOPS. 15 



Extensor abductor from near top of carapace, descending posterior to flexors, to be 

 inserted in proper apodeme at hinder outer part. 



In the flexed position the limb comes forward and inward, and the setae of the palpi- 

 form process pass through the notch of the retracted postoral bar into the mouth. In 

 full extension the limb does not go beyond a right angle with the body. 



Yb. Inner Maxilliped (PL I. fig. 7.) — This is about equal in length to the first and 

 half the third joints of the outer. It is less compressed, and is squarish in section at base. 



First joint, nearly half the total length, produced inwards, upwards, and forwards at 

 base into a strong toe-like apodeme, elongated, constricted just above its base, bearing 

 on its inner face, halfway up, a palpiform process with two setae, a lower one, short and 

 tapering, and an upper one, distinctly jointed at its insertion, both plumose, with distant 

 coarse setse ; and above this process the limb bears a similar plume, but shorter and finer. 



Second joint elongated, nearly equal to the first; an oblique ridge of teeth runs 

 from the base obliquely across to the posterior edge at about three fifths its length, and 

 is continued along that edge to the end of the joint. The anterior edge is ventricose, with 

 the greatest swelling beyond the middle, bearing a stout tapering spine with a few scat- 

 tered setae. 



Third joint short, almost triangular, wider behind, its outer angle produced into a 

 short process, bearing a spine similar to that of the preceding joint, but longer. 



Fourth joint a little knob bearing on its anterior edge a spine similar and equal to the 

 last, and at its apex a hooked spine half the length of the former, and a shorter pale 

 hair. 



The Proper Muscles of the Inner Maxilliped are as follows : — 



A levator of the palpiform process, originating from the postmaxillary apodeme, and 

 inserted in the inner edge of the limb just beyond the process, depression being effected 

 by its elasticity. 



An extensor and flexor of the second joint, inserted into its base, and originating in the 

 apodeme of the limb. 



An extensor and flexor of the third joint, inserted into its base, and springing from the 

 base of the second joint. 



An extensor and flexor of the fourth joint, inserted into its base, originating with the 

 last two muscles, and running a little nearer the middle of the limb through the second 

 and third joints. 



These muscles render the limb distinctly prehensile. 



Extrinsic Muscles of the Inner Maxilliped : — 



An adductor flexor and abductor extensor spring from the sides of the carapace below 

 and behind those of the outer maxilliped, and are inserted into the basal apodeme of the 

 limb. 



A second adductor springs from the postmaxillary apodeme, and is inserted on the 

 posterior side of the limb, near its base. 



This limb, in flexion, has its distal processes passing into the mouth, and, in extension, 

 like the outer ramus, is never more than perpendicular to the body. 



