364 BULLETIN OP THE BUREAU OP FISHERIES. 



Salmincola carpenteri (Packard). 



,4 chtheres carpenteri Packard, Annual Report U. S. Geol. and Geog. Survey of the Territories for 1873. p. 612, i text figure. 

 Salmincola carpenUri Wilson, Proc. U. S. Nat. Mus., vol. 47, p. 616, pi. 33, fig. 54-60. 



Host and record of specimens. — From the gills of " txont " in a tributary of the East River, Colo. , and 

 from "salmon" at Battle Creek, Colo.; the former host has been identified by R. R. Gurley as Salmo 

 mykiss. 



Remarks. — Neither this nor any of the other species of the genus have ever been found associated 

 with any glochidium, but not because the two are uncongenial. Very few, if any, of the species of 

 trout and salmon have been examined for glochidia, because usually the streams and lakes in which 

 they live are inhabited by only a few mussels, none of which are of any value commercially. Further- 

 more, neither of the two kinds of fish are found in those localities where artificial infection has been 

 tried, and thus there has been no chance to ascertain whether they will take the glochidia or not. But 

 the susceptibility of tliese fish to copepod parasites would lead us to suppose that they would make 

 good hosts for glochidia. In all probability future examination will discover glochidia upon some of 

 them, and if artificial propagation is tried in lakes as well as rivers there would seem to be no reason 

 why these fish could not be used as carriers for the glochidia. 



Achtheres pimelodi KrfSyer. (PI. lxxi.) 



Achtheres pimelodi Kr0yer. Naturhistorisk Tidsskritt, 3 Raekke. 2 bd., p. 272, pi. 17, fig. 5a, 5b; Wilson, Proc. V. S. Nat. 

 Mus., vol. 47, p. 628, pi. 38. 



Host and record of specimens. — Both sexes have been obtained from the gill arches of various catfish; 

 from Ictalurus punclaius at Cincinnati, Ohio; from Ameiurus nebulosus at Put-in Bay, Ohio; from Iclalu- 

 rus anguilla and Leptops olivaris at Fairport, Iowa. From the former of the last two a female was 

 obtained and numbered 47726, U. S. National Museum; from the latter a female with ripe eggs, which 

 hasbeen given catalogue no. 47771, U. S. National Museum. 



First copepodid larva. — The egg strings of the ripe female just mentioned were detached and the larvse 

 hatched out in an aquarium, August 22, 1914. These larvae differed in several important particulars 

 from those of ambloplitis already described (Proceedings U. S. National Museum, vol. 39, p. 208), as 

 may be seen by the following: 



Cephalothorax elliptical, the breadth to the length as 1 1 to 17, not enlarged anteriorly over the base 

 of the second antennae; head separated from the first thorax segment by lateral notches, but without a 

 well-defined groove ; posterior lobes large and evenly rounded. Attachment end of the filament excep- 

 tionally large, somewhat quadrate in dorsal view, and close to the frontal margin; coiled portion of the 

 filament also tmusually long and situated far back in the cephalothorax. Dorsal color patch about the 

 same size as the attachment end of the filament, shield-shaped, and placed nearly at the center of the 

 cephalothorax. Posterior portion of the body made up of four segments, all the same width, but dimin- 

 ishing in length backwards, the foiuth one about one-third the length of the first, which latter carries 

 on its sides, the rudiments of a third pair of swimming legs. Anal laminae twice the length and more 

 than half the width of the last segment, so that they overlap on the midline, each armed with two large 

 sword-shaped, jointed setae on the inner side and three shorter ordinary ones on the outer margin. 



First antennae four- jointed and heavily armed with setae; second antennae similar to those in amblo- 

 plitis; mandibles short and thickset, made up of a single spherical joint tipped with a stout spine and 

 carrying a triangidar palp on the outer margin. First maxillae two-jointed, the basal joint spherical, 

 the terminal one long and pointed; second maxillae with a strongly swollen, almost spherical basal joint 

 and a stout terminal claw, bent at right angles near its center; maxillipeds comparatively slender, with 

 two imarmed joints and a stout curved claw. Swimming legs similar in all respects to those of amblo- 

 plitis, biramose, each ramus one-jointed, the exopods tipped with four plumose setae, the endopods 

 with six. 



Total length, 0.45 mm.; width of cephalothorax, 0.20 mm. 



Remarks. — The most noticeable differences between the present larva and that of ambloplitis are 

 the lack of separation of the first thorax segment, the comparatively enormous attachment filament, the 

 swordlike setae on the anal laminae, and the bulky, swollen form of the mandibles, first and second 

 maxillae. In the present larva also the mandibles have a rudimentary palp while the first maxillae 

 have none, the reverse being the case in ambloplitis. There are four patches of pigment, but the dorsal 

 patch and the posterior ventral one are relatively much larger than the others, which are reduced to 

 minute spots. 



