630 PROCEEDINGS OF THE NATIONAL MUSEUM. 



females without egg strings, taken from the mouth of Lucoperca in 

 the Danube River at Hesse, Germany. This lot is numbered 39576, 



U.S.N.M. 



A second lot of two females with egg strings was taken from the 

 gills of Perca Jluviatilis at Yamtland, Sweden, and was obtained by 

 exchange with the University of Stockholm. It has been numbered 

 43580, U.S.N.M. 



Specific characters o//ewaZe.^I!ephalothorax nearly as large as the 

 body and ovate, inclined at right angles to the trunk axis, the trunk 

 as wide as long and distinctly segmented, obovate in outHne and 

 flattened dorso-ventrally ; abdomen small, triangular and mthout 

 joints; each egg string often as large as the body and ellipsoidal, 

 containing about 75 eggs. First antennae slender, exceptionally 

 long, and distinctly three-jointed; second pair with a simple exopod, 

 armed with short spines and considerably curved toward the endopod; 

 the latter also simple and tipped with a single spine; first maxillae 

 tliree-partite, the three rami all on a level; second maxillae stout 

 and tapered considerably anteriorly; bulla as wide as both arms at 

 their tips and cup-shaped; claw on the maxillipeds smooth and 

 rather slender. 



Color, a grayish-white. 



Total length (without egg strings), 4.5 mm. Length of cephalo- 

 thorax, 2.2 mm. ; of trunk, 2.3 mm. ; of egg strings, 2.5 mm. Width 

 of cephalothorax, 2 mm. ; of trunk, 2.3 mm. ; of egg strings, 1.66 mm. 

 ipercarum, the generic name of the host.) 



Speciic diameters of male. — Cephalothorax fuUy as long as the 

 trunk, widest posteriorly, with concave lateral margins; body indis- 

 tinctly segmented, a flattened sphere in shape, ending in a blunt 

 tip posteriorly, where it is armed with two short anal laminae. First 

 antennae very slender and three-jointed as in the female; neither 

 ramus of the second pah- armed as well as in the female; fii-st max- 

 Olae three-partite; second maxillae long, with a wi'inkled basal joint 

 and a small chela on the tip of the terminal jomt; claw of maxillipeds 

 short and stout, shutting down against a small papilla on the inner 

 margin of the basal joint. 

 Color, a creamy white. 



Total length, 1.5 mm. Greatest width, 0.66 mm. 

 Remarlcs. — Both sexes of this species have been admirably described 

 and figured by both Nordmami and Claus, the latter also giving the 

 internal anatomy and several stages in the development. Hence 

 there have been here included only the distinguishing characters and 

 two outline figm-es for comparison. These plainly show that it is 

 different from all the American species, and thus far it has never 

 been found upon any American host, although it is widely distrib- 

 uted throughout Europe. Like the American species, amhloplitis, 



