274 BRITISH ENTOMOSTRACA. 



1. Lepeoptheirus Stromii. Tab. XXXII, figs. 8, 9. 



Caligus Stromii, Baird, Trans. Berw. Nat. Club, 1847. 



Laxe luus, Strom, Kiobenhavn. Selsk. Skrift., x, 23, t. 7, f. 3-7. 



Caligus vespa, Edw. Thompson, Ann. and Mag. Nat. Hist., xx, 248. 



Description. — Female. Carapace oval. The frontal 

 plates not very prominent. Thorax about the same length 

 as carapace ; last articulation narrower at upper extremity, 

 broad posteriorly, and terminating in two rounded lobes. 

 Abdomen long and narrow, nearly as long as the last joint 

 of thorax. Caudal plates of moderate size, and giving off 

 several stout, short, plumose setae. Sternal fork short, 

 with simple branches. The horny tubercles on the median 

 line of posterior portion of thorax large, and simple. 

 Oviferous tubes long, three or four times the length of the 

 animal. Length of body (exclusive of tubes) about half 

 an inch. 



Male. The male is much smaller than the female. The 

 carapace is oval, and much longer in proportion to the 

 thorax than in the female ; thorax oval-shaped, narrow, 

 and notched rather than lobed posteriorly ; the outer 

 angles in form of a small protuberance, and armed with 

 two or three short seta3. Abdomen much shorter than in 

 female ; terminal setae of caudal appendages longer and 

 finely plumose. 



This species approaches very nearly the description of 

 the Caligus vesjja of M. Edwards. The vespa, however, 

 is only three lines in length, and has the carapace narrow 

 in front, and very broad posteriorly, and is as broad as 

 long, while in this species the carapace is almost an exact 

 oval, and the animal is half an inch in length. In vespa, 

 the horny tubercle at the base of the thorax is small and 

 setiferous ; and in this species it is simple, and of consi- 

 derable size. 



Hab. — Berwick Bay ; taken ofi" the salmon, August 

 1844, W. B. Salmon at Berwick, Dr. Johnston. County 

 Down, off" the Salmo trutta, August ; iSalmo salar, July ; 



