REPORT ON THE CRUSTACEA MACRURA. 807 



The first pair of antennas has the peduncle about one-fourth the length of the 

 rostrum, and carries at its base a stylocerite that is at first broad and then suddenly 

 sharp pointed, and about half the length of the first joint ; the succeeding two joints are 

 short and subcylindrical, and terminate in two flagella that are broken off short. 



The second pair of antennas carries a scaphocerite that reaches to about half the 

 length of the rostrum ; it is waved on the outer margin, which is stout and rigid, and 

 terminates in a small latero-apical tooth ; it is separated from a median ridge by a longi- 

 tudinal furrow, and the inner margin is also strengthened by a ridge that becomes 

 stronger as it approaches the base, and is fringed with long and sparsely ciliated hairs. 



The first pair of gnathopoda is generic in character. 



The second pair is also chiefly generic ; the terminal joint does not reach quite to 

 the distal extremity of the scaphocerite, and is long, narrow, lanceolate, and hirsute ; the 

 penultimate is rather longer, cylindrical, and smooth ; the antepenultimate suddenly 

 increases in diameter, gradually widens and flattens towards the base, and probably 

 represents the ischium and meros united ; the basis is short and carries an ecphysis 

 that is three-fourths the length of the antepenultimate joint ; the coxa is short and 

 supports a thick disc-like plate projecting from the outer side of the posterior surface, 

 from which a rigid mastigobranchial rod also projects. 



All the pereiopoda except the posterior pair carry a moderately long ecphysis, and a 

 short, ovate, mastigobranchial plate. 



The third somite of the pleon projects dorsally to a point that lies close against the 

 surface of the fourth somite, and the sixth, which is longer than the two preceding, is 

 laterally compressed. 



The telson is subequal with the outer branch of the rhipidura, and armed on each 

 side, on the dorso-lateral angle, with seven small spinules. 



All the specimens are more or less damaged, but one female was heavily laden with 

 ova, which are small and round, therefore clearly demonstrating the species to be 

 specifically distinct from Nematocarcinus lanceopes, which was taken in the Indian Ocean. 



Other specimens that I have placed under separate specific names were taken 

 associated with Nematocarcinus longirostris, and bear to it a considerable resemblance 

 in all points excepting the relative length of the rostrum, and the consequent amount of 

 ornamentation on it. This is more apparent in those that depart slightly from the exact 

 form of the type specimen. 



There were nine or ten specimens taken, all of them well grown, though none quite 

 so large as the one selected for description. Each of these varies in some degree, 

 especially in the length of the rostrum as compared with that of the carapace, and in 

 some instances in the number of the teeth also, but in all these instances the teeth on 

 the lower margin have the posterior subequal with or in advance of the distal extremity 

 of the peduncle of the first pair of antennas. 



