60 PROCEEDINGS OF TEE NATIONAL MUSEUM. vol.53. 



12303 and 12304; from the ale^Yife, Pomolohus pseudoharengus^ at 

 Woods Hole, Cat Nos. 130G9 and 42327; from the pursey minnow, 

 Cyprinodon variegatus, at Woods Hole, Cat. No. 8287; from the 

 anchovy, " EngrauUs vittafus,''^ in New York City market, Cat. No. 

 42349; from tlie Avhite perch, Morone amerkana, at Woods Hole, Cat. 

 Nos. 82SG and 8288; no host and no locality given. Cat. Nos. 617G and 

 35202. 



The eight specimens in lot No. 12313 are heavily infested with 

 algae, but were removed from their host with exceptional care and 

 are finely preserved. Since Le Sueur's original specimens have been 

 lost these may well serve as surrogate types of the species. 



Specific characters of female. — General body form elongate slender, 

 and graceful, the three body regions distinctly separated. Head 

 terminal and globular, with a conical proboscis as large as itself at- 

 tached to the ventral surface at right angles to the long axis. 

 Cephalothorax furnished with slender, filamentous, radiating chitin 

 horns, usually five in number and unbranched. But there may be any 

 number of these horns from 2 to 9; when there are only two they are 

 on a level Avith the dorsal surface at the extreme anterior end of the 

 head (fig. 29) ; when there are five they are arranged radiately around 

 this portion of the head like the spokes of a wheel (fig. 27). But 

 there may also be a smaller horn on either side of the base of the 

 second antennae, and two others, one on either side of the thorax, 

 on a level with the dorsal surface and opposite the fourth pair of 

 legs (figs 28 and 40). These horns may be of any length or they may 

 be reduced to mere knobs. When there are five, the typical number, 

 they are nearly equal and are arranged one dorsal, two lateral, and 

 two latero-ventral. When they differ in length the two lateral are 

 usually the longest and the dorsal one the shortest. 



The free thorax or neck is somewhat enlarged immediately behind 

 the head through the bases of the legs, then quickly becomes fiiliform 

 and has the same diameter back to the trunk. The latter is elongate- 

 conical, the point of the cone at the base of the neck, the outer sur- 

 face smooth and without any traces of segmentation. Normally a 

 section of this trunk would present a circular outline, but in pre- 

 served material it often becomes flattened laterally. The Ggg strings 

 are the same diameter as the neck and one-half longer than the 

 body. In immature specimens the trunk is greatly reduced in length 

 and width, while the neck is proportionally increased in length, 

 and the egg strings then are often three times the length of the 

 whole body (fig. 20). The abdomen is a short, stout, and blunty 

 rounded cone, on a level with the dorsal surface of the genital seg- 

 ment, one-third the length and three-fourths the width of the latter, 

 and destitute of anal laminae or setae. 



