Miscellaneous. l93 



As in all the Grapslcepones, the pleal j^lates of the female of O. 

 Edwnrdsi are finely and regularly fringed. ' The maxillipede has 

 exactly the same form as in G. Messoris, Kossm., but it is distin- 

 guished specifically by the absence of all deiiticulation. There are 

 two dorsal bosses, upon the middle of the sixth and seventh thoracic 

 segments, that on the seventh segment being the larger. 



Hitherto the males of Gnqjsicepon were unknown. That of G. 

 Edwardsi is very remarkable. By its much smaller amount of 

 degradation than in the other Ceponians it approaches the Leidyce, 

 The pigmentation is very strong ; the segments of the pleon become 

 narrower very rapidly from in front backwards ; each of them bears 

 hiartlculate pleal feet. The lateral appendages of the pygidium, 

 although not so long as those of the males of Leidyce, are very pro- 

 minent and inflected towards the ventral surface. The median 

 ventral bosses extend upon the first three pleal segments and are 

 sometimes much pigmented. 



We have only been able imperfectly to study the Cepon parasitic 

 upon Trapezia dentifrons. Having at our disposal only a unique 

 specimen collected by J. M. Barnard (Jlde A. Garrett), we have been 

 obliged to abstain from any dissection ; but the mere external 

 examination of this parasite, which we name Grapsicepon amicofum, 

 possesses much interest. In fact there still exists a certain amount 

 of hesitation as to the systematic position of the Trapeziie. Prof. 

 H. Milne-Edwards made these Crustacea, under the name of ^'Can- 

 ceriens qnadrilatires," into a group intermediate between the Cato- 

 metopa and the Cyclometopa, with which he connected them through 

 the Eripldo'. E. Nauck, relying upon the characters furnished by 

 the stomachal armature, regards the Trapezioi as quite distinct 

 from the Cyclometopa, and inclines to approximate them to the 

 division Heterodonta, in which he places the Gelasimidae and Pinno- 

 therida3. 



The study of Grapsicepon amicorum seems rather to furnish argu- 

 ments in favour of Milne-Edwards's opinion. The female is very 

 large relatively to the size of the host. It is of a brownish colour 

 and its dorsal integument is shining, like that of Trapezia. There 

 are no dorsal bosses, which approximates this species to Cepon typus, 

 from which it differs completely, however, by the form of the coxal 

 pads. The plates and appendages of the pleon are like those of 

 Grapsicepon ; the male is much pigmented ; the ventral bosses 

 exist only upon the first segment of the pleon ; they are voluminous 

 and covered with denticulate scales. The pleopoda are biarticulate, 

 with the terminal joint rudimentary. The lateral lobes of the 

 pygidium are much shorter than in Grapsicepon Edivardsi. In fact 

 the character's of this species appi'oximate it rather to the Ceponians 

 parasitic upon the Grapsi than to the Leidyce, parasites of the 

 Gelusimi ; therefore, to avoid the establishment of too many generic 

 groups, we place it provisionally in the genus Grapsicepon. 



We give the name of Porfunicepon Hendersoni to the Ceponian 

 parasite of Thahimita calJianassa, Herbst (Goniosoma, A. Milne- 

 Edwards). This species appears to be pretty frequent at Madras, 



Ann. d- Mag. N. Hist. Ser. 6. Vol. ii. 13 



