REPORT ON THE CRUSTACEA MACRURA. 653 



The pleopoda are biramosc, narrow, subfoliaceous and tapering; the inner branch 

 supports a long club-shaped stylamblys, the extremity of which is furnished with 

 cincinnuli. The first pair has the rami short and unequal, and attached to a peduncle 

 that has the extremity produced as a flat, squamous plate. 



The females of this genus are extremely prolific, if I may judge from the number of 

 ova that ai*e borne by the few specimens obtained. The ova generally are small, smaller 

 than those of Heterocarpus, and in Nothocaris ocellus the specimen obtained cannot 

 carry less than ten thousand eggs, if the number on each of the pleopoda be equal to 

 those on the first pair. 



The branchial arrangement of the genus corresponds with that of Heterocarpus and 

 Pandahis, as shown in the following table, and differs from that of Plesionika in the 

 absence of a pleurobranchia from the second pair of gnathopoda. 



Pleurobranohiae, 

 Arthrobrancbiae, 

 Podobranchise, 

 Mastigobrancbiae, 



Observations. — In this genus all the mastigobranchise are of a rudimentary character, 

 excepting those of the first pair of gnathopoda, and terminate in small hooks as in 

 Plesionika ; they vary in number and form in the different species, but never terminate 

 in a straight process as in Pandalus and Pandalopsis. 



Geographical Distribution. — There are three or four species of this genus in the 

 Challenger collection, and these were all found in the Eastern Archipelago, between New 

 Guinea and the Philippine Islands, in depths of less than 150 fathoms. I am inclined to 

 think, from an examination of Professor A. Milne-Edwards' figures, that several species 

 that he has classified as belonging to Pandalus belong to this genus, more particularly 

 Pandalus sagitarius, Pandalus genicidatus, Pandalus longicarpus and Pandalus 

 brevirostris, taken during the expedition of the "Travailleur." 



Nothocaris rostricrescentis, n. sp. (PI. CXIV. fig. 1). 



Carapace dorsally smooth over the cardiac and lateral regions, anteriorly carinated 

 over the gastric region and produced to a long, upwardly curved, crescent-shaped rostrum, 

 which is smooth on the upper surface from near the apex to the orbits, armed with two 

 teeth at the apex and five spines and two teeth on the frontal crest. A small antennal 

 tooth stands near the outer canthus of the orbit, and a very small one at the fronto-lateral 

 angle. 



Pleon smooth, and but slightly compressed ; third somite arcuate and posteriorly 



