642 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvm. 



1 : 



separation of such species as had no lunules. It was also described 

 independently \>y Baird in 1847 under the name Caligus stromii, which 

 he changed in 1850 to Lepeophtheirus stromii. This name of Baird's 

 is the one subsequently retained by Bassett-Smith and T. Scott, the 

 former of which gives Kroyer's name as a S3 T nonym under it. 



But if the two species are identical, as there seems to be no doubt, 

 then Kr63 T er's name has a priority of nine years over Baird's, and must 

 be retained. 



The species is common upon the salmon of our coasts as well as those 

 of European waters, and often attains a large size. 



Some of the females examined by the author measured 22 mm. in 

 length, and that, too, although the}" had been preserved in alcohol. 

 They can be readily distinguished from other species by the extreme 

 length and slenderness of the egg strings and by the metallic luster so 

 common on the dorsal surface. 



The males are very scarce, the material in the entire National Museum 

 collection yielding but a single specimen. So far as known, no figure 

 of the male has ever been published previous to the one here included. 

 The following are the lots in the National Museum collection : Cat. No. 

 8030, from salmon at the Tyne, England, used for identification of the 

 American specimens. No. 8109, four specimens, including the single 

 male from the gills of a salmon, locality not given. No. 8117, from 

 the king salmon at Kenai, Alaska. No. 8489, fifteen specimens, from 

 Ungava, Labrador, found on "salmon and sea trout." No. 12666, 

 from salmon at St. Johns, Newfoundland. No. 36073, from salmon at 

 East Orland, Maine. No. 41840, two specimens, from "Dolly Varden 

 trout" in Alitak Bay, Alaska. No. 6017, from Onc/wrkynchus gor- 

 huscha at Port Chatham, Cooks Inlet, Alaska. An unnumbered lot, 

 from Sal/mo solar, found at Rigolet, Labrador. 



The salmon at East Orland, Maine, must have been -from fresh water, 

 and several of the other species mentioned occur as entirely landlocked 

 forms in various localities. There can be very little doubt, therefore, 

 that this parasite is another instance of one which can remain upon its 

 host during the passage of the latter from salt to fresh water. It 

 would be of great interest to ascertain whether it remains upon such 

 forms as have become entirely landlocked. 



LEPEOPHTHEIRUS PACIFICUS Gissler. 



Plate XXV, figs. 304-310. 



Caligus pacificus Gissler, 1883, p. 885, figures in the text. 



Female. — Carapace about half the entire length, elliptical, a little 

 longer than wide; frontal plates short and narrow, but well defined. 

 Posterior sinuses wide and shallow, leaving a broad median lobe, 

 more than half the entire width, and not projecting back of the lateral 

 lobes. Thoracic area relatively small and well rounded posteriorly; 



