166 AUSTRALIAN MALACOSTEACA. 



Rostrum reaching the second joint of the peduncle of the 

 external antennae, emarginate at the apex, with six teeth on 

 either side, and beset with fasciculi of hairs between ; a longitu- 

 dinal line in the middle, which, however, does not reach to the 

 apex. Anterior border of the carapace beset with two large 

 teeth above the insertion of the external antennee, and two small 

 ones below. Gastric region wrinkled. First, third, fourth, and 

 fifth abdominal segments always with two, the second with ten 

 teeth on the lateral borders ; third, fourth, and fifth with a fringe 

 of hairs on the hinder half of the lateral borders. Telson with 

 an elevated transverse ridge which developes into a small point. 

 Both the internal and the external rami of the sixth pair of 

 abdominal appendages with two keels on the internal ramus, one of 

 these is on the outer border and without spine, the other has 

 four spines, and between the two are three more spines ; on the 

 external ramus both keels are curved and without spines, the 

 outer the stronger, and the external border armed with sixteen 

 strong teeth. \E. von M.~] 



Cape York (Darnel). 



Family THALASSIN1DJS. 

 Abdomen and caudal appendages narrow. External maxilli- 

 pedes pedif orm. 



G-enus Thalassina, Latreille. 

 Carapace short, narrow, and much elevated ; gastric region 

 small and limited behind by a deep groove ; front with a small 

 triangular rostrum. External maxillipedes of moderate length, 

 pedif orm, the second joint armed with spiniform teeth on its 

 internal face. Eirst pair of legs narrow and moderately elongated, 

 but tolerably stout, very unequal ; hand with a tooth at its inf ero- 

 distal angle forming a tooth-like immobile finger ; mobile finger 

 very large ; legs of the second pair much compressed and rather 

 broad. Abdomen very long, narrow, semi- cylindrical, and nearly 

 of the same thickness in all its extent. Telson small, rami of 

 the appendages of the sixth abdominal segment almost linear. 



313. Thalassina maxima. 



Thalassina maxima, Hess, Archiv fiir Natur., xxxi., p. 163, 

 pi. vii., fig. 18 (1865). 



