ISOPODS OF NORTH AMERICA. 



131 



TjxuditirH. — West Indies; Gulf ol" Mexico: Caril)})can Sea; Mouth 

 of Exuma Sound; Bay of Bengal. 



Depth. — 955 fathoms; 740 fathoms. 



Body o])lono--ovate. nearly two and a half tinx's lonoej- than wide, 

 38 mm. : IHi mm. 



Head wider than long-, Vl nun. : "21 mm., with the anterior maruin 

 produced in a median point which meets the apex of th(^ triangular 

 frontal lamina. The eyes are 

 lart^e, composite, and are situ- 

 ated on the inferior side of the 

 head. The tirst pair of antennn 

 have the basal article larjje. 

 about as wide as lono-; the sec- 

 ond is about as lono* as the tirst; 

 the third is half as long as the 

 second; there is a small scale 

 articulated to the end of the 

 third article of the peduncle; 

 the tiagellum is composed of 

 forty-six articles and extends 

 one-fourth the length of the 

 tirst thoracic segment. The sec- 

 ond pair of antenna? have the 

 tirst article short; the second is 

 almost at right angles to the tirst 

 and is about 2 mm. long; the 

 third is about as long as the sec- 

 ond; the fourth is about 3 mm. 

 in length; the fifth is 4 nun. long. 

 The flagellum is composed of 

 about sixty-six articles and ex- 

 tends to the middle of the fourth thoracic segment. The maxillipeds 

 are composed of seven articles. The frontal lamina is triangular in 

 shape, with the apex contiguous with the median point of the frontal 

 mai'gin of the head. 



The tirst segment of the thorax is the longest, being 1(> mm. in 

 length. The second and third arc subequal. and each is 6 nnn. long. 

 The fourth and tifth are each 5 mm. in length. The sixth and seventh 

 are each 4 nmi. long. The epimera are distincth^ separated on all the 

 segments with the exception of the tirst, and are large plates with th<» 

 outer post-lateral angle produced in the last four ])eyond the posterior 

 margin of the segments. 



The six segments of the abdomen are distinct, the tirst live being 

 subequal in length. The sixth or terminal segment is wider than 



Fig. UJ.— Bathynomus giganteus (After Edwakds 

 AND Agassiz). Dorsal view. 



