REPORT ON THE CRUSTACEA MA CRURA. 647 



considerably beyond the rostrum, which is more than half the length of the animal. 

 Both flagella are slender, but the outer is more robust towards the base. 



The second pair of antennas has the second or basisal joint armed on the outer and 

 under side with a small sharp tooth, and carries a scaphocerite that has nearly parallel 

 sides, the outer being rigid and terminating in a small distal tooth that reaches to about 

 half the length of the rostrum. The third joint terminates in a flagellum that reaches a 

 little beyond the longest flagellum of the first pair. 



The second pair of gnathopoda is long, slender, and pediform, the second joint or 

 basis is furnished with a slender branch, the third or ischium is short, the fourth or meros 

 is extremely long and slender, as is also the fifth joint or carpos, and the sixth or 

 propodos is about half the length of the carpos, and terminates in a flattened point, the 

 margins of which are notched for the reception of hairs or spines. 



The first pair of pereiopoda is more slender and longer than the second pair of 

 gnathopoda, having the meros and propodos about half the length of the carpos and 

 terminating in a rudimentary dactylos (fig. 2k). The second pair of pereiopoda is 

 unequal, that on the right side being shorter and more slender ; the carpos is long and 

 multiarticulate, the propodos scarcely longer or broader than the ultimate articulus of 

 the carpos ; the pollex and dactylos are small and form a perfect but minute chela. The 

 three posterior pairs are very long, reaching forwards very considerably beyond the 

 extremity of the rostrum ; the meros is long, and furnished on the posterior or lower 

 margin with a series of slender, sharp, spine-like teeth, from which the name of the 

 species is derived ; the carpos is very long and more slender than the meros, as is also 

 the propodos, while the dactylos is short and styliform. The rest of the animal offers no 

 peculiar feature of specific interest, except that the posterior pair of pleopoda, which forms 

 the tail-fan, is longer than the telson. 



The branchias in this species deviate from the typical arrangement of the genus in 

 having no mastigobranchial appendage attached to the several pairs of pereiopoda ; they 

 may be tabulated as follows : — 



Pleurobranchise, 

 Arthrobranchiae, 

 Podobranchise, 

 Mastigobranchiae, 



Observations. — All the specimens in the collection, except one, appear to be males, 

 and bear a close comparison with Pandalus styhpus, A. Milne-Edwards, which was taken 

 in the Atlantic during the expedition of the " Travailleur," at a depth of 530 fathoms. 

 It differs, however, in several points of more or less importance. The first pair of antennas, 

 for instance, has the flagella much longer, being twice the length of the rostrum ; the 

 serrature of the rostrum is more alike on the two margins ; the second pair of pereiopoda 



