766 ON A NEW CRUSTACEAN GENUS. 



these are to one another. I liave proposed, therefore, to establish 

 for it a new genus, which may be defined as follows : — 



DiPTEROPELTIS. 



Caiman, Abstract P. Z. S. 1912, p. 34 (May 28th). 



Argulidaj with the so-called maxillse modified as suckers ; with 

 the preoral papilla present, but without a spine ; with antennules 

 and antennte veiy minute, imperfectly segmented ; without large 

 spines or hooks on under side of carapace, body, or appendages : 

 without furcal rami on the abdominal lobes ; with the lateral 

 wings of the carapace greatly elongated. 



Genotype. — D. hirundo Caiman. 



It is to be noted that the single species of Chonopeltis, 

 C. inermis Thiele *, is known only from a single specimen (from 

 Lake Nyasa). It is not at all impossible, therefore, that the 

 antennules, if they are as small as in Diptero2:>eltis, may have 

 escaped observation, and it is even possible, though less probable, 

 that an unarmed preoral papilla may be present. Should this 

 prove to be the case it is doubtful whether, in spite of the great 

 difference in the form of the carapace, the separation of Diptero- 

 peltis from Chonopeltis covild be maintained. 



EXPLANATION OP PLATE LXXXIV. 



(The magnifications given are only approximate.) 



Fig. 1. Di^teropeltis Mrundo. Female (holotype), from the dorsal side, x 3. 



2. Anterior part of body of same specimen from \entral side. The suckers 



have been drawn apart and slightly backwards. In the preserved 

 specimens they meet in the middle line and entirely conceal the preoral 

 papilla. X 6. 



3. Antennule and antenna, x 450. 



4. Tip of oral cone from antero-ventral aspect, x 100. 



5. Part of membranous margin of one of the suckers, x 160. 



6. Maxilliped. x 20. 



7. Leg of iirst pair, x 20. 



8. Leg of second pair, x 20. 



9. Leg of third pair, x 20. 

 10. Leg of fourth pair, x 20. 



Figures 3-10 are drawn from one of the paratypes. 



* Thiele, Zool. Anz. xxiii. p. 47 (1900) ; Mitth. Zool. Mus. Berlin, ii. p. 44. 

 figs. 110-116 (1904). 



