170 AUSTRALIAN MALACOSTBACA. 



Carapace ornamented with squamiform tubercles, and armed 

 on the median line with a series of spines, of which the three 

 longest occupy the gastric region ; an oblique crest, which arises 

 from the internal orbital angle, reaches the branchial region, and 

 bears three strong spines, of which two are situated above the 

 orbit. External antennae large and strongly toothed, their ante- 

 penultimate joint nearly triangular, armed with two strong teeth 

 on its external border, and ornamented above with a crest which 

 is directed obliquely and terminates at the anterior angle ; the 

 last joint armed with six strong teeth on the anterior border. 

 Abdomen sculptured above, and presenting on the posterior 

 border of each segment a rather deep median excavation. Legs 

 slender. Length about 3 in. ; colour brown, with transverse 

 red lines on the abdomen. 



Thursday Island, Torres Straits (W.A.H., H.M.8. "Alert"). 

 Occurs in the Mediterranean, and on the coasts of Japan. 



G-enus Thenus, Leach. 



Carapace transverse; sides not incised. Eyes- oblong, situated 

 at the external angles of the carapace. Rostrum bilobate. 

 Branchiae 21. 



319. Thenus orientalis. 



Scyllarus orientalis, Eabr., Suppl., p. 399 ; Latr., Hist. Nat. 

 Crust., t. vi., p. 181 ; Encycl., pi. 314 ; Desmarest, Consid., 

 p. 182, pi. xxxi., fig. 1. 



Thenus orientalis, M.-Edw., Hist. Nat. Crust., t. ii., p. 286. 



Carapace much depressed and verrucose ; a small obtuse 

 crest ornamented with three teeth on the middle line ; rostrum 

 armed with two thick divergent cornua. A spine at the internal 

 angle of the orbit, two on its upper border, and one at its 

 posterior angle ; another tooth on the upper surface of the 

 carapace a little behind the orbit, and a deep fissure on the 

 external border. A strong spine in the middle of the posterior 

 border of the tergum of the fifth ring of the abdomen. 



Swan River (Dana). Eound also in the Indian Ocean. 



