356 BULLETIN OF THE BUREAU OF FISHERIES. 



ERGASILID^. 



Ergasilus lanceolatus, new species. (PI. Lxvi, fig. 40-46.) 



Host and record of specimens. — Twenty females with egg strings were obtained from the gills of the 

 gizzard or hickory shad, Dorosoma cepedianum, at Lock 2 1 on the Cumberland River in Kentuclr>', July 

 16, 1911. This lot has been given catalogue no. 43555, U. S. National Museum, and from it has been 

 selected a single female (catalogue no. 43556, U. S. National Museum) to serve as the type of the new 

 species. 



Specific characters of female. — General body form long and narrow, lanceolate; cephalothorax ellip- 

 tical, one-half longer than wide, almost squarely truncated posteriorly, projecting a little anteriorly, 

 with a small knob at the center of the anterior margin. First three free segments narrowed regularly 

 backwards, the first of them (second segment) a little more than half the width of the carapace and 

 about twice the width of the fourth segment; fifth segment very short and narrow; genital segment one- 

 half wider tlian the fifth segment, with strongly convex sides. Abdomen the same width as the fifth 

 segment, three-jointed, the basal joint longer than the others; anal laminse small, rectangular in out- 

 line, each armed with two setse, the inner of which is 7 or 8 times the length of the outer one. 



First antennse six-jointed, the basal joint much longer than any of the others and armed with a 

 very long, jointed seta, the other joints carrying shorter and simple setae. Second antennje not very 

 large but powerful, basal joint short but much swollen and projecting strongly on the outer margin; 

 second joint with a small stout spine near the center of the inner margin; terminal claw long, stout, and 

 strongly curved. 



The mouth parts project much more strongly than in any species thus far examined, both the 

 upper and the under lips standing out prominently to form a long and sharp cone, from whose summit 

 project on either side the long first maxilla. Mandibles exceptionally large and thickset, the terminal 

 portion turned forward at right angles to the basal. The latter carries on its anterior margin, just out- 

 side the narrow neck, a bluntly rounded process projecting forward; the cutting blade is triangular in 

 outline and armed with setae along its inner margin only. 



The palp is exceptionally long; starting from the posterior corner of the basal joint and reaching 

 nearly to the center of the cutting blade with a row of corrugations along its outer margin. 



First maxillae small but projecting strongly, each armed with two plumose seta; second maxillae 

 much smaller than the mandibles, but otherwise of the usual size and pattern. Endopods of the first, 

 third, and foiuth legs longer than the exopods; exopods of second legs longer than the endopods; all 

 three joints of the endopods of the first legs and the two basal joints of the endopods of the second legs 

 armed with minute teeth along their outer margins; exopod of fourth legs two- jointed, the basal joint 

 twice the length of the terminal one. The arrangement of spines and setae is as follows: First exopod, 

 i-o, 0-0, 11-5; endopod, o-i, o-i, n-4; second exopod, iii-o, i-i, 1-6; endopod, o-i, 0-2, 1-4; third 

 exopod, 1-^3, o-i, 0-6; endopod, o-i, 0-2, 1-4; fourth exopod, 0-0, 1-4; endopod, o-i, o-i, 1-2. 



The egg strings when first extruded are conical, largest at the base and tapering to a single egg at 

 the tip; when fully developed they are cylindrical and considerably shorter than the body; eggs in 

 5 or 6 rows, about 10 eggs in a row. 



Color (preserved material), a uniform light brovvTi without pigment markings. 



Total length, i mm.; cephalothorax, 0.60 mm. long, 0.40 mm. wide. Length of egg strings, 0.60 

 to 0.80 mm. 



{lanceolatus, lanceolate, alluding to the general body shape.) 



Remarks. — This species is not associated as yet with any glochidium, but may well take the place of 

 cceruleus or cenlrarchidarum or versicolor. 



Its presence on the shad indicates that this fish would make a good host for some of the gill glochidia 

 as well as for those already found upon its fins. Like other parasites found upon the herrings and their 

 close relatives, this species does not infest any fish except its immediate host, and hence it is not likely 

 to be found except on the gizzard shad. 



Ergasilus nigritus, new species. (PI. lxvii.) 



Host and record of specimens. — Ten females, most of them with egg strings, were obtained from the 

 gills of the largemouth bass Micropterus salmoides, in the Mississippi River at Fairport, Iowa, July 20, 

 1914. They have received catalogue no. 43562, U. S. National Museum, and become cotypes of the 



