26 



MARINE ISOPODS FROM THE PHILIPPINE ISLANDS. 



minal segment longer than wide and with the posterior margin rounded. Uropoda 

 long and narrow and extending beyond the extremity of the abdomen. The pleopods 

 are large and conspicuous in a dorsal view, and surround the entire abdomen. 



The legs are prehensile, the last pair being abruptly longer than the others, with the 

 merus, carpus, and propodus elongated. 



The type of the genus is Pleopodias elongatus, new species, the description of which 

 follows. 



Pleopodias elongatus, sp. nov. 



Body oblong-ovate, a little over 2.33 times longer than wide, 9 mm.: 22.66 mm. 

 Length of head and thorax 16 mm. Color yellow, covered with black and brown 

 arborescent spots, very close together and more or less confluent in the dorsal region 

 of the body. 



Head almost as long as wide, 3 mm.: 3.5 mm., triangulate with the front produced 

 in a truncate extremity, which is 1 mm. wide. The eyes are large, oval in shape, and 

 situated in the postlateral angles of the head; they extend 

 half the length of the lateral margin. The first pair of an- 

 tenna? have the first three articles dilated and gradually in- 

 creasing in size (the first is hidden in a dorsal view by the 

 frontal process of the head) ; the following five articles become 

 gradually narrower, but all are about equal in length. The 

 first antennae extend to the middle of the first thoracic segment. 

 The second antennae are composed of twelve articles and ex- 

 tend to the middle or a little beyond the middle of the second 

 thoracic segment; the first two articles are 

 short and subequal; the next two are sub- 

 J \ equal and each is about as long as the first 

 S s^l two taken together; the fifth is very long, 



LI twice as long as the fourth; the sixth is 1.5 

 / 7 times as long as the fourth and is shorter 

 Sj than the fifth; the following six articles are 



quite short, each being half as long as the 

 \ |\ sixth or less than half. 



\y The first three segments of the thorax and 



seventh leg. x the sixth are about equal in length, each 



FIG. 25.-Pleopodias elongatus. X 2f . bein §'. 2 mm - lon g; the fourth segment is 3 



mm. in length; the fifth 2.5 mm., and the 

 seventh 1 mm. The head is slightly immersed in the first segment of the thorax, the 

 anterolateral angles of which extend one-third the length of the eyes. Epimera are 

 present on all the segments with the exception of the first; they are narrow plates, 

 extending to about the middle of each segment. 



The abdomen is not abruptly narrower than the thorax, but the segments gradually 

 become narrower from the first to the terminal segment, the first being 6 mm. wide at 

 the base and the sixth segment 2 mm. wide. The last thoracic segment is 8 mm. wide. 

 The first abdominal segment is about half as long as the following four segments. All 

 four segments measure only 3 mm. in length. The sixth or terminal segment is long 

 and narrow, 3.66 mm. long and 2 mm. wide. Its extremity is rounded. The uropods 

 extend about 0.66 mm. beyond the extremity of the terminal segment; the branches 

 are equal in length, about 2 mm. each, and are long and narrow, with parallel sides and 

 rounded extremities. The pleopods are large and conspicuous in a dorsal view, as 

 they extend below the extremity of the abdomen and project at the sides. 



The legs are all prehensile, the bases without carinas. Seventh pair abruptly longer 

 than the others and with the propodus, carpus, and merus elongated. 



