552 THE VOYAGE OF H.M.S. CHALLENGER. 



The second pair of antennae (fig. 4c) has the peduncle a little longer than that of 

 the first, the basal tooth is very small and unimportant, and the scaphocerite has the 

 squamous plate continuous with the outer margin to near the distal extremity, where it 

 terminates in a sharp tooth ; the flagellum of this pair of antennae is delicately slender 

 and longer than the entire animal. The second pair of gnathopoda extends to a little 

 beyond the peduncle of the second antennae, and carries a branch that reaches to the 

 distal extremity of the antepenultimate joint. 



The first pair of pereiopoda (figs 4k, Ah') is long and unequal on the two sides ; the 

 larger being sometimes on one side, sometimes on the other. The meros of the larger 

 hand is produced to a point on the upper distal angle and is fringed with hairs. The 

 carpos is triangular and produced anteriorly above and below. The propodos is long and 

 flattened on each side, the upper and lower margins being nearly parallel ; a short 

 distance behind the articulation of the dactylos there is a deep and receding notch, which 

 brings about the formation of a sharp pointed tooth -like process behind it; in a corre- 

 sponding position on the lower margin there is a similar tooth-like process. The pollex is 

 directed horizontally forward and has the margin on each side elevated into a ridge, 

 between which the edge of the dactylos, which is furnished with a blunt tuberculose 

 tooth, impinges. The left hand (fig. 4h') is long, narrow, and nearly cylindrical, being 

 slightly compressed laterally ; the fingers are about as long as the palm. In the specimen 

 which, from being the most perfect, I have selected as the type, and from which I have 

 taken the figures, the fingers are not so long as they are in some of the other specimens. 



The second pair of pereiopoda has the carpos six-articulate, the first articulus being 

 a little longer than the second, and the two equal to half the carpos. 



In the Bay of Bengal, off Waltair, on the coast of Madras, a species was taken by 

 the late Sir Walter Elliot that resembles this in all respects, except in the presence of 

 the deep notch on the upper and lower margins. 



Alpheus rapax, Fabricius (PI. XCIX. fig. 1). 



Alpheus rapax, Fabricius, Suppl. Entom. Syst., p. 404. 



„ ,, Milne-Edwards, Hist. Nat. Crust., t. ii. p. 353. 



„ ,, de Haan, in Siebold's Fauna Japonica, Crust., p. 177, tab. xlv. fig. 2. 



Rostrum reaching nearly to the extremity of the first joint of the peduncle of the 

 first pair of antennae, laterally compressed, producing a small carina that extends 

 backwards and fades away on the gastric region. Orbital lobes separated from the 

 dorsal carina by a deep groove. 



The first pair of antennae has the stylocerite short, flat, and broad, with a small tooth 

 at the anterior extremity, which reaches nearly to the end of the first joint; the second 



