NO. 1701. NORTHWEST PACIFIC ISOPODS— RICHARDSON. 93 



HOLOTELSON, new genus. 



Head of normal size. Basal article of first pair of antenna* with 

 the distal posterior angle not produced in an acute process. 



Seventh thoracic segment in male produced backward in two small 

 processes, one on either side of the median line. These processes are 

 much smaller in the female, but are indicated. 



First segment of abdomen produced in the median line on the 

 I30sterior margin in a small tubercle, represented in both sexes. 



Terminal segment of abdomen, with the posterior margin pro- 

 duced backward in one long median process, at the base of which 

 on either side is a small rounded process. The median process is 

 shorter in the female, and the lateral processes are also reduced. 



The branches of the uropoda are similar in size in the male, the 

 exojDod of the female being somewhat smaller than the endopod. 



The second pleopod of the male is furnished with a stylet. 



The exopod of the third pleopod is jointed near the extremity. 



Both branches of the fourth and fifth pairs of pleopods are fleshy, 

 with transverse folds, and are without marginal 

 setpe. The exopod of the fifth pleopod is jointed. 



This genus belongs in the section euhranchiatm 

 of Hansen, but differs from the other genera in that 

 section in not having the terminal segment of the 

 abdomen emarginate. 



The type of the genus is Holotelsoii titberculatus^ 

 the description of which follows: 



HOLOTELSON TUBERCULATUS, new species. 



Body oblong-ovate, about twice as long as wide, '''"o n''™cu'la: 

 5^ mm. : 11 mm. tds. pirst.an- 



Head wider than long, rounded in front, and with 

 a small median point. Eyes round, composite, and 

 placed at the post-lateral angles. The first pair of antennse have 

 the basal article large and dilated, about twice as long as wide; 

 the second article is short, about as wide as long, and nearly as 

 wide as the basal article; the third article is narrow and elongate, 

 being only half as wide as the second article and twice as long; 

 the flagellum is composed of fourteen articles and extends to the mid- 

 dle of the first thoracic segment. The second antennse have a flagellum 

 of fifteen articles and extend to the middle of the second thoracic 

 segment. 



The first segment of the thorax is about one and a half times longer 

 than any of the following five segments which are of nearly equal 

 length. The lateral parts of these segments are short and broad and 

 produced at the post-lateral angles in rounded triangular processes. 



TENNA OF FEMALE. 

 X 15J. 



