504 BUIjLETIN" 15 8, UNITED STATES NATIONAL MUSEUM 



Female. — Head subquadrangular, about the same width and 

 length ; first and second thoracic segments very short and consider- 

 ably narrower than the head; third segment separated from the 

 fourth by a distinct groove; posterior processes short and blunt and 

 convergent, so that their tips usually touch; urosome 2-segmented 

 and very short. First antennae stout, 2-segmented, with scattered 

 apical spinules ; second antennae with a stout apical claw ; mandibles 

 slender and acuminate ; maxilla toothed only distally, without a palp. 

 Swimming legs biramose, rami flattened and covered with minute 

 spinules. Total length, 5 mm. 



Male. — Unknown. 



Remarks. — This species has never before been reported from 

 American shores; it may be recognized by the structure of the 

 swimming legs. 



ACANTHOCHONDRIA PHYCmiS (Rathbnn) 



FiGUBE 299, 



Chondracanthus phycldis Rathbun, Proc. U. S. Nat. Mus., vol. 9, p. 320, pis. 

 9, 10, 1886. 



Occurrence. — Fifteen females, most of them with attached males, 

 were taken from the gills of the common hake {Urophycis tenuis)., 

 captured off Marthas Vineyard by Rathbun in 1883. 



Distribution. — Not found outside the present area. 



Color (preserved material). — Body a yellowish or dingy white; 

 oviducts a light yellow or yellowish buff. 



Female. — Head ovate, narrowed anteriorly, the frontal margin 

 straight or slightly concave; in side view the dorsal surface is 

 strongly arched and the thickness in the region of the mouth is equal 

 to the greatest width. First and second segments narrower than the 

 head and imperfectly separated ; third segment abruptly widened to 

 twice the width of the first segment, separated from the fourth seg- 

 ment by a partial groove and lateral indentations. Genital segment 

 small ; abdomen a single subglobular segment ; no caudal rami. First 

 antenna cylindrical, 2-segmented; second antenna with a swollen 

 basal segment and a stout apical claw; each leg 1-segmented, nearly 

 cylindrical, and slightly bilobed at its distal end. Total lengih, 

 5-5.5 mm. 



Male. — Body pyriform ; head fused with first two thorax segments 

 (the second segment partly separated dorsally) and much larger 

 than the rest of the body; trunk indistinctly 4-segmented; caudal 

 rami slender, conical, acuminate. First antennae apparently made up 

 of a single segment; second antennae with a swollen basal segment 

 and a stout apical claw; mandible falcate, acuminate, fringed with 

 fine saw teeth; maxilla with a palp, the outer margin of the distal 



