REPORT ON THE CRUSTACEA MACRURA. 



257 



table. I have arranged these several species in a tabular form so that the points of 

 resemblance and separation may be the more readily appreciated, merely premising that 

 the petasma in the male and the thelycum in the female are constant in the same 

 and dissimilar in separate species. 



Penseus incisipes, n. sp. (PI. XXXIV. fig. 2). 



Eostrum straight, slightly elevated, armed with seven to nine teeth on the upper 

 surface, and one on the gastric region. Eye large, about half the length of the rostrum. 



First pair of antennas having flagella as long or nearly as long as the peduncle. 

 Second pair of antennae three times as long as the entire animal. First pair of pereiopoda 

 armed with one tooth. Second pair armed with one; third with none. Chelae long and 

 slender. Posterior pair of pereiopoda long and slender, dactylos flattened, meros notched 

 on the under or posterior margin. First pair of pleopoda in the male having the petasma 

 long, narrow, and double-headed at the extremity ; second pair furnished with a large 

 tubercle on the anterior surface of the inner ramus ; telson unarmed and shorter than the 

 outer plates of the rhipidura. 



Length of male, 88 mm. (3'5 in.). Female, 31 mm. (l - 25 in.). 



Habitat— Station 190, September 12, 1874; lat. 8° 56' S., long. 136° 5' E.; Arafura 

 Sea, south of Papua ; depth, 49 fathoms ; bottom, green mud. One female. 



Station 203, October 31, 1874; lat. 11° 6' N., long. 123° 9' E. ; off Panay, 

 Philippine Islands ; depth, 20 fathoms ; bottom, mud. Three males and one small 

 female. 



The specimens of this species in the collection are three males, and two small females ; 

 they are smooth and almost pobshed, and tomentose in patches corresponding with various 

 regularly situated elevations and depressions that mark the animal all over. The rostrum 



(ZOOL. CHALL. EXP. — PART LII. 1886.) Fff 33 



