84 PROCEEDINGS OF THE NATIONAL MTJSEVM. vol.53. 



convolutions, bent at right angles ^Yhen it enters the neck and pass- 

 ing insensibly into the intestine, which is enlarged in the posterior 

 neck and trunk; rectum very short and narrow. Ovaries fused on. 

 the midline of the dorsal surface, in the small of the back, and folded 

 around the sharp curve in the body wall; oviducts passing around 

 the intestine to the ventral surface and thence to the vulvae ; cement 

 glands ventral to the oviducts and plainly convoluted. 



External generic characters of cojyepodid male. — Head and first 

 thorax segment fused; second, third, and fourth thorax segments 

 free; fifth and genital segments fused; abdomen one-jointed; anal 

 laminae armed with short setae. Two pairs of antennae, second pair 

 chelate; a pair of mandibles; two pairs of maxillae, second pair 

 uncinate ; a pair of stout maxillipeds. 



Internal generic characters of Copepodid male. — Mouth tube at 

 right angles to the head axis; stomach and intestine straight and in- 

 distinguishable; rectum very short; large digestive glands along 

 either side of the cephalothorax. Testes paired and situated in the 

 posterior portion of the cephalothorax; sperm ducts straight and 

 dorsal to the intestine; spermatophore receptacles in the genital 

 segment large and elliptical. 



Type of the genus. — Lernaeocera branchialis (Linnaeus), first 

 species. 



{Lernaeocera, Lernaea, and xepas, a horn). 



KEY TO THE SPECIES. 



1, Head without anchor processes, simple, and filiform ; body not flexed ; egg 

 strings not coiled; no appendages (13.50 ram.)* 



ahyssicola (Brady), 1883, doubtfuL 



1. Head with simple unbranched processes ; neck long and slender ; body 

 with a strong curve or simple flexure; egg strings sometimes regu- 

 larly coiled 2 



1. Head with branched processes ; neck short and stout ; body with double 



sigmoid flexure ; egg strings always loosely coiled 3 



2. Head small, subspherical ; genital segment and abdomen covered with a 



den.se filamentous growth; egg strings coiled in a rftjular spiral (20 mm.) 



lotellac (Thompson), 1889. 



2. Head small, funnel-shaped, joined to the neck at an acute angle; genital 

 segment aud abdomen covered with scattered tufts of setae (22.50 mm.) 



ri(iida (Kr0yer), 1863. 



2. Head large and spherical ; genital segment only slightly wider than the neck 



and separated from the abdomen by a constriction ; no .setae or filaments 

 (50 mm.) lumpi (T. Scott), 1901. 



3. The posterior horn the only one developed, as long as the whole body, in 



line with it and profusely branched; egg strings in a few loose coils 



(15 mm.) branchialis, var. (Hesse), 1891. 



3. Genital segment with but a single curve ; processes flat and short, but much 

 bi-anched ; egg strings stout and their coils larger than the entire genital 

 .segment (8 mm.) minuta (T. Scott), 1900. 



* Average total length of species. 



