ISOPODS OF ISrORTH AMERICA. 



r>33 



Fig. 677.— Hyper- 

 gnathus tex- 



ENSIS. UKOPOD. 



■: 51 1. 



The five anterior segments of the al)domen are subequal in length, 

 the first two not hoing covered at the sides by the seventh thoracic 

 segment. The sixth or terminal segment is posteriorly 

 produced to a triangular extremity. Th(> uropoda 

 extend some distance beyond the terminal segment of 

 the body. The peduncle (\\'tends beyond the terminal 

 abdominal segment. Thi^ outer branch is twice as long- 

 as the peduncle. The iinier bi-anch is placed at the 

 inner distal angle of the peduncle and is less than half 

 the length of the outer branch. 



The color is a light yellow, with iriH^gular markings 

 of brown on the posterior margins of the segments and 

 on the lateral parts. The head is thickly covered with 

 brown mai'kings, which on the produced portion are 

 arranged in definite transverse lines, but on the I'emain- 

 ing surface are arranged irregularly around small, 

 rounded, yellow areas. The abdomen is very closely 

 covered with the brown as is also the posterior half of the outer uropod. 



Types, Cat. No. 32075 U.S.N.M., collected by H. S. Barber in Texas. 



114. Genus ACTONISCUS Harger. 



Head produced in three lobes, a median Iol)e and an antero-lateral 

 lobe on either side. Second pair of antennje with the fiagellum com- 

 posed of four articles. First maxilla? with inner lobe furnished at 

 the tip with two bunches of hairs; outer lobe furnished with numer- 

 ous spines. Second maxilltB small, not larger than first maxillaj, 

 with no indication of lobes at the tip. Masticatory lobe of maxilli- 

 peds truncate at the tip; palp with joints indistinctly defined. 



Abdomen not abruptly narrower than thorax; the first two segments 

 are covered laterall}' by the last thoracic segment; lateral parts of the 

 third, fourth, and fifth segments well developed; terminal segment 

 with apex not produced. 



Basal article of the uropoda large, dilated, and simulating the epim- 

 era of the fifth abdominal segment; both brancnes of the m'opoda 

 short, styliform, the outer one inserted a))oiit the middle of the inner 

 margin of the peduncle. 



ANALYTICAL KEY TO THE SPECIES OF THE GENUS ACTONISCCS. 



Middle frontal lobe of head acute; antero-lateral lobes rounded. Second and third 

 articles of fiagellum of second antenna? equal and longest. Terminal segment 

 of abdomen broadly rounded. Surface of body smooth. Fifth article of the 

 peduncle of the second autenn;e longer than the fourth; terminal article of 

 fiagellum minute. Post-lateral angles of the first thoracic segment not produced. 



Actoniscus ellipticus Harger 



