40 MARINE ISOPODS FEOM THE PHILIPPINE ISLANDS. 



The six segments of the abdomen are short and distinctly separated. Pleural 

 lamellae are present on all except the last, but these lamellae gradually become smaller. 

 The sixth or terminal segment is very small. There are five pairs of double-branched 

 pleopuda, both branches being large, leaf -like, and tuberculate; they extend a 

 considerable distance beyond the lamellae of the abdominal segments. The uropoda 

 are attached to the sixth or terminal segment of the abdomen and consist of a pair of 

 long leaf -like appendages as long as the branches of the pleopoda. There are five 

 pairs of incubatory lamellae, which do not quite enclose the marsupial cavity. The 

 lamellae are tuberculate. The seven pairs of legs are prehensile and have the basis 

 furnished with a high carina. 



The male is narrow, elongate. The head is large, with the anterior margin rounded. 

 Eyes are distinct. All seven segments of the thorax are distinct, with lateral margins 

 not contiguous. The abdomen is short, composed of five segments, the fifth or ter- 

 minal segment being small and triangular in shape . There are no pleopoda or uropoda, 

 but on either side of the median line on the ventral side there is an elevation and 

 thickening on the first four abdominal segments. 



Only two specimens, a male and a female, were collected, at station 5197, Baliscasag 

 Island, S. 22 mi. (9° 52 / 30" N., 123° 40' 45" E.), at a depth of 174 fathoms, in green 

 mud. Type specimen, catalogue number 40926, United States National Museum. 



Genus ORBIONE Bonnier. 



The uropoda are biramous in the female of this genus and not single-branched as 

 described by Bonnier. This genus differs from Gigantione Kossmann, as it also does 

 from Parapenseon, in having all six segments of the abdomen of the female lamellate, 

 while in those genera only five segments of the abdomen of the 

 female are lamellate. It also differs from Gigantione in the appear- 

 ance of the male, which is figured herein for the first time. 



Orbione penei Bonnier. 



Orbione penei Bonnier, Travaux de la Station Zool. de Wimereux, vm, 1900, 

 p. 280-282, pi. xii. 



Locality: Station 5181, Antonia Island (S.), S. 63° W., 6.60 mi. 

 (11° 36' 40" N., 123° 26' 35" E.), at a depth of 26 fathoms, in 

 mud and fine sand. Bonnier's specimen was from Hongkong. 



A male and a female were collected by the Albatross and the 

 151- male is here figured. Heretofore the male has been unknown. 



Genus PARAPENiEON Richardson. 



The uropoda are biramous in the female of this genus and not single-branched as 

 heretofore stated, agreeing in this respect with Orbione Bonnier as amended (see above) . 

 It differs, however, from Orbione in having the abdomen of the female with five seg- 

 ments lamellate, while in Orbione the abdomen of the female has six segments lamel- 

 late. The female of Parapenxon differs from the female of Pleurocrypta in having 

 the uropoda biramous (they are single-branched in Pleurocrypta) and in having pleura 

 developed on the segments of the thorax. 



The female of this genus is similar to the female of Gigantione Kossmann, but the male 

 differs from the male of that genus in having all the segments of the pleon united 

 and not distinct as in Gigantione, and in the absence of pleopoda and uropoda, which 

 are well developed in the male of Gigantione. 



