314 AMPIIIPODA NOUMALIA. 



the first ; flagellum uniurticulatc, scarcely cui-vcfl at the extremity, 

 furnished throiipjli the entire length of the infenor margin wUh a 

 few nulimeutary denticles, on the inner surface with a row of 

 small tubercles, and tipped at the extremity with a few hairs. In- 

 ferior antennae much longer than the superior, and possessing a 

 flagellum that consists of one very long articulus and one (ter- 

 minal) short and pointed. First pair of gnathopoda having the 

 carpiis longer and broader than the propodos ; propodos slightly 

 arcuate, tapering, fm-nished at the infero-anterior angle with a 

 margiaal row of short stiff spines that correspond with the in- 

 teiior margin of the dactylos. Second pair of gnathopoda having 

 the carpus inferiorly produced, about half the length of the inferior 

 miu'gin of the propodos. First -pair of pereiopoda having the cai-pus 

 broadly dilated, ovate, iafero- anterior margia oblique, fringed with 

 a few hairs ; propodos arcuate, inner margin less so, single, armed 

 at the distal extremity only with a few long and short cilia ; 

 dactylos subulate. 

 Length -j^,ths of an inch. 



Hah. (In the Atlantic ?) Latitude of La Plata (MS. label). 



The rest of the animal corresponds with the description given of 

 T. antarctica. In fact, the species so much resemble each other, that, 

 had not their respective size and locality been very distinct, they 

 probably would have been passed over as varieties of the same. 



This specimen is also one of those belonging to the valuable collec- 

 tion in the Museum of the Jardin des Plantes. It was collected 

 duiing the fii-st ' Expedition de I'Astrolabe.' It is named in honoiu' 

 of the founder of the genus, to whom I am indebted for permission 

 to examine his large collection and drawings of Amphipoda. 



3. Themisto Gandichaudii. (Plate L. fig. 10.) 



Themisto Gaudichaudii, Giieriii-MeneviUe, Mhn. de h Soc. (THist. 

 Nat. de Paris, iv. pi. 23. f. c. 



M.-Edicards, Ann. des Sc. Nat. xx. ; Hist, des Crust, iii. p. 84. 



Cephalon round. Superior antennte about the length of the eephalon, 

 stouter than the inferior, and composed of four joints ; the first is 

 about one-third the length of the antennce, the second and third 

 are short, and the fourth (flagellum) is longer than all, tapering to 

 the point a:id ciu-ving downwards. Inferior antennae twice the 

 length of the superior, and also composed of foui' joints, of which 

 the first is very short, the second longer, the third as long as the 

 first two, and the fourth (flagellum) longer than the three preceding; 

 the flagellum seems to be composed, as in the superior antennae, of a 

 great number of short articuli. First pair of gnathopoda not differ- 



