28 PEOCEEDINGS OF THE NATIONAl. MUSEUM vol.80 



rounded and curves inward toward the midline. The outer portion 

 folds abruptly over dorsally and curves backward in a long pennon, or 

 streamer, approximately parallel to the body axis, and nearly as long 

 as the copepod itself. This streamer tapers gradually to a narrow 

 point, and its edges are frayed into jagged teeth and fingerlike 

 processes. These chitinous outgrowths make this species unique, 

 although they are foreshadowed in a way by the asymmetrical proc- 

 esses in other species. 



The antennae and mouth parts are similar to those of other species 

 of the genus, with certain variations. Chief among the latter are 

 the differences found in the chewing blade of the mandible. The 

 drawing of this (pi. 1, G) shows that it is peculiarly powerful and 

 armed with a row of formidable teeth. If its structure is any indi- 

 cation of habits this species must be very predacious, living upon all 

 sorts of smaller creatures in the plankton. Its large size and its 

 strong maxillae and maxillipeds enable it to seize and overpower 

 these animals, which can then be chewed up by the mandibles. The 

 fifth legs are much reduced in size and appear stunted when com- 

 pared with those of P. vieadii. The endopods are more than half 

 the length of the exopods and end in two stout spines of approxi- 

 mately the same length. 



Specific characters of nude. — The male is slightly smaller than the 

 female (A and C of Plate 1 are drawn to different scales). Its body 

 is relatively thicker and its abdomen much longer, although still be- 

 low the average for Pontella males. The lobes at the posterior corners 

 of the last thoracic segment are distinctly asymmetrical, the right one 

 being considerably longer and more sharply pointed. The abdomen, 

 however, is practically symmetrical, but the last two joints are tele- 

 scoped into the preceding joint so far as to be almost indistin- 

 guishable. 



The right, or grasping, antenna is characterized b}' a long and 

 stout fingerlike process projecting from the anterior margin of the 

 seventeenth segment. This is armed along its outer margin with a 

 row of four stout spines, which will at once distinguish this species 

 from meadii, or indeed from any other species of the genus. One or 

 two other species have such a process, but it is not armed with spines 

 and is attached to a different segment. There is also a long and 

 slender seta, or spine, on the fused thirteenth-fourteenth segment, 

 similar to that in other species, but longer and hooked at the tip. 



The second antennae and mouth parts are of the usual form; the 

 fifth legs are very similar to those of the preceding species, but rela- 

 tively much stouter, and the nonchelate ramus is considerably longer 

 and armed with extra spines. 



