162 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



Fig. 142.— Tridentella 

 viRGiNiANA. First 



MAXILLA. X Slf. 



Fig. 143. — Tridentella Virgin- 

 ian a. Abdomen. 



Color, light brown. 



Two specimens were collected by the U. S. Bureau of Fisheries 

 steamer Albatrom in Chesapeake Bay. 

 • %>6^— Cat. No. 6350, U.S.N.M. ' 

 The following- description is of two specimens from southern Cali- 

 fornia Avhich 1 have not been able to separate from 

 the species from the Atlantic coast: 



Body oblong-ovate, nearly twice as long as wide, 

 5 mm. : 9 nmi. 



Head wider than long, li mm.: 2^ mm., with the 

 anterior margin rounded and produced in a small 

 median point, which 

 meets the anterior mar- 

 gin of the frontal lamina. 

 There is a small tubercle 

 situated at the base of 

 the median point. The 

 eyes are small, round, 

 composite, and placed at 

 the post-lateral angles. 

 There are four tubercles 

 on the dorsal surface of 

 the head between the eyes, two close to the anterior margin and the 

 other two close to the posterior margin, one on either side of the 

 median line in each series. 



The tirst pair of antennse have the first two articles short and sub- 

 equal; the third is about twice as long as 

 the second. The tiagellum is composed 

 of twelve articles and extends to the pos- 

 terior margin of the first thoracic seg- 

 ment. The second pair of antennte have 

 the first article a little longer than the 

 second and equal in length to the third; 

 the fourth is twMce as long as the third; 

 the fifth is a little longer than the fourth. 

 The flagellum is composed of twenty arti- 

 cles and extends to the posterior margin 

 of the third thoracic segment. The maxil- 

 lipeds are composed of seven articles. The 

 mandible has a palp of three articles. The 

 frontal lamina is short and broad. 



The first segment of the thorax is twice as long as any of the follow- 

 ing segments, which are subequal. The epimera are distinctly sepa- 

 rated on all the segments with the exception of the first. The last 



Fig. 144. — Tridentella virgix 



IANA. X 6. 



