282 AUSTEALIAN MALACOSTRACA. 



Sub-Family Cymothoince. 



Abdomen multi-articulate, the segments free. Caudal appen- 

 dages not ciliated. 



& 



Genus Ceratothoa, Dana. 



Body very convex. Head deeply encased in the anterior 

 segment of the thorax (the antero-lateral lobes of which do not, 

 however, reach to its anterior margin), narrowed anteriorly, and 

 subacute at the extremity, which does not cover the bases of the 

 antennae. Abdomen at base very much narrower than thorax, 

 six-jointed, the first five segments very short, the last broad, 

 transverse. First (inner) pair of antennae shorter than the 

 second, with the bases in contact, first two or three joints dilated 

 and flattened. Femoral joints of the last four pairs moderately 

 thickened and dilated. Caudal appendages small. \M.~] 



486. Ceratothoa trigonocephala. 



Cymothoa trigonocepliala, Leach, Diet, des Sc. Nat., tome xii., 

 p. 353 ; Milne-Edwards, Hist. Nat. des Crust., t. iii., p. 272 

 (1840) ; Cr. M.Thomson, Trans. N. Z. Institute, Vol. xi., p. 233; 

 Heller, Beise der Novara, Crust., p. 148. 



Head small, triangular, having the antero-lateral borders very 

 concave, below the antenna?, and the front narrow but obtuse 

 and a little more prominent than the base of the internal 

 antenna?. Eyes very distinct. Anterior border of the first 

 thoracic ring advancing slightly on the head in an angular form, 

 so as to form a tooth on the middle line ; antero-lateral prolon- 

 gations of moderate length, narrowed in front, but rounded and 

 not reaching the level of the base of the external antenna 1 . 

 Length about 20 lines. \_M.-E.~] 



Australia. Eound also on the coasts of China and New 

 Zealand. 



Sub-Family (Er/athoines. 



Caudal appendages ciliated. Abdomen multi-articulate, the 

 segments free. 



