662 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



of those which really prey upon our common fishes. The species are 

 usually not conspicuous, and are very likely to be overlooked by or- 

 dinary observers. The Lernjeans, which include the commonest and by 

 far the most injurious species, may be attached to any part of the fish? 

 and should be specially looked for upon the gills and about the gill- 

 openings and throat. It is important that specimens should be collected 

 in large numbers for study. For this purpose, they should be preserved, 

 while quite fresh, in small bottles of alcohol or other strong spirit. 



Family Argulid^. 

 Argulus Catostomi Dana and Herrick. 



American Journal of Science, Ist series, vol. xxx, p. 388, 1836, and vol. xxxi, p. 297, 

 plate, 1837. 



Parasitic on the " sucker," a species of Catostomiis, in Mill River, near 

 New Haven, Conn., in both fresh and brackish water. 



Argulus FunduU Kroyer, (Bidrag til Kundskab om Snyltekrebsene, 

 p. 20, pi. 2, fig. 1, 1863,) should, perhaps, be included in this list, as it is 

 described as found upon Fundulus limhatus Kroyer, from New Orleans, 

 but it is not stated whether from salt or fresh water. 



Family Caligid^. 

 Lepeophtheirus Salmonis Kroyer. 



Caligm Salmonis Kroyer, Naturhistorisk Tidsskrift, vol. i, p. 622, 1837, vol. ii p. 



13, 18, pi. 6, fi{^. 7, 1838; Edwards, Hist. Nat. des Crustac6s, vol. iii, p. 455 ; 



Steenstrup and Llitken, Bidrag til Kundskab om det aabne Havs Suyltekrebs 



og Lernajer, p. 15, 1861. 

 Caligiis respa Edwards, op. cit., vol. iii, p. 456. 



Lepeoptheirus Stromii Baird, British Entomostraca, p. 274, pi. 32, figs. 8, 9, 1850. 

 Lepeophtheirus Salmonis Kroyer, Bidrag til Kundskab om Snyltekrebsene, p. 137, 



pi. 17, fig. 1, in Naturhistorisk Tidsskrift, III, vol. ii, 1863. 



Parasitic on the salmon of our eastern coast and of Europe. It is 

 perhaps more properly a marine than a fresh- water species, but is car- 

 ried by the salmon far up the fresh water rivers. 



Ergasilus FiincluU Kroyer, (Bidrag til Kundskab om Snyltekrebsene, 

 pp. 228, 238, pi. 11, fig. I, 1863,) from Fandulus limhatus Kroyer, from 

 New Orleans, is perhaps to be added to this list. \ 



Family Lern^opodidje. 



ACHTHERES PiMELODi Kroyer. 



Bidrag til Kundskab om Snyltekrebsene, pp. 272, 275, pi. 17, fig. 5, 1863. 

 Upon a specimen of Ptinelodus macidatus, from Oincinnati, according 

 to Kroyer, from whose work I translate the following diagnosis : "Arms, 

 by which the animal is attached, much longer than the head, slender, 

 nearly straight ; bulla (the extremity of the united arms) very small, 

 sessile. Body annulated into five segments, and marked with two dor- 

 sal, longitudinal sulcations. External ovaries equa ling or exceeding the 



