CYAMIDAE 



3i3 



Antenna 1, ist-3rd joints subequal or 3rd slightly shorter, 1st about half length of 



head plus 1st segment. Antenna 2 extending almost 

 as far as apex of 1st joint of antenna 1 . Maxilliped, 

 palp rudimentary even in a juvenile of 4 mm., but 

 fully developed in one of 2 mm. 



Gnathopod 1 , 5th joint in <$ ovate with prominent 

 rounded tooth on inner margin; in $ narrow ovate, 

 margin even. Gnathopod 2, 5th joint in S with 

 prominent pointed tooth on inner margin near 

 hinge; in $ inner margin nearly straight, without 

 tooth. 



Peraeopods 5-7 not very strongly expanded, no 

 ventral point on antero-distal corner of 2nd joint, 

 3rd joint as broad as 2nd, and only a little less broad 

 than 4th, which has antero-distal corner rounded 

 or at most subacute (not acute) and postero-inferior 

 angle rounded, not prominent, 5th joint narrow 

 ovate. 



Branchiae single on both segments 3 and 4, 

 rather thick, equal in length to peraeon segments 



Fig. 173. Paracyamus gracilis (R. de V.). 3-5 together, shorter in ? ; accessory appendages 



a. Dorsal view of $. b. Gnathopod 1 <j. i n g short, double on both segments, absent in $. 



c. Gnathopod I $. d. Gnathopod 2 $. Length: S up to io mm., ? up to 8 mm. 



e. Gnathopod 2$. /. Branchiae?. 



Remarks. The above description is based on 

 South African specimens in the South African Museum. This species seems to be always 

 inextricably mixed up with the individuals of Cyamus ovalis. They appear to be confined 

 to the head region of the whale. 



Genus Isocyamus, Gerv. and Bened. 

 Gervais and Beneden, 1859 (Exp. Meth. Regne Anim., 1), quoted from Stebbing, 1888, p. 316. 

 Gnathopods 1 and 2 unequal. Antenna 2 reduced to three joints. Maxilla 2 without 

 outer lobes. Maxilliped, lobes fused, without trace of palp. Unguis of gnathopod 1 

 distinct from the dactylus. Branchiae single on both segments 3 and 4. 



Remarks. Although the characters of this genus were not stated by the original 

 authors, the type, delphini, was designated. The genus may well be resuscitated on the 

 above characters. 



Isocyamus delphini (Guer.) (Fig. 174). 



Guerin-Meneville, 1836 (Iconogr., in), p. 25, pi. 28, fig. 5. 

 Stebbing, 1888, p. 163. 



Milne Edwards, 1840 (Hist. Nat. Crust., in), p. 114. 

 Brandt, 1872 (quoted from Stebbing, 1888). 



40 



