766 ON A NEW CRUSTACEAN GENUS. 



these are to one another. I have 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). 



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

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

 and antennfB very 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 Dijoterojjeltis, 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 could be maintained. 



EXPLANATION OF PLATE LXXXIV. 

 (The magnifications given are only approximate.) 



Fig. 1. Dipteropeltis hirundo. Female (holotype), from the dorsal side, x 3. 



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



have been drawn apart and slightly backw.ards. 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 first 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). 



