26 BULLETIN 15 8, UNITED STATES NATIONAL MUSEUM 



separate species. It is worthy of note that Rathbiin in his manu- 

 script notes regarded it as a distinct species and added the following 

 interesting observation: "Several thousand specimens of a Sagitta, 

 probably Sagitta elegans, came up in the trawl wings at Stations 985 

 and 986, Fish Hawk. Nearly every one of these Sagittas had a single 

 copepod of the present species in its digestive tract, forming a large 

 bright pinkish spot, distinctly visible to the naked eye. This would 

 indicate that the Sagittas feed upon these copepods and that the latter 

 constitute an important factor in their diet. 



Genus MEGACALANUS Wolfenden, 1904 



Head separated from the first segment, or fused with it; fourth 

 and fifth segments separated; first antennae reaching for many seg- 

 ments beyond the caudal rami. All 5 pairs of legs biramose, the 

 rami 3-segmented; anterior surface of the distal segment of the 

 first basipod with or without a stout hook, to which is articulated a 

 strong plumose seta; terminal segments of second, third, and fourth 

 exopods each with three spines on the outer margin; fifth legs sym- 

 metrical, inner margins of basipods naked. Caudal rami short, each 

 with six setae, the third inner one a little the longest. One species. 



MEGACALANUS PRINCEPS (Brady) 



FiGtJBE 12 



Calanus princeps Bkady, Voyage of H. M. S. Challenger, vol. 8, pt. 23, Copepoda, 



p. 36, pi. 4, figs. 3-7, 1883. 

 Macrocalunus princeps Sabs, Bull. Mus. Oceanogr. Monaco, no. 26, p. 7, 1905. 

 Megacalanus princeps Saes, Rfeultats des campagnes scientifiques accomplies 



sur son yacht par Albert I", Prince Souverain de Monaco, fasc. 69, p. 14, pi. 



3, 1925. 



Occurrence. — Three females from trawl wings at Stations 954, 994, 

 Fish Hawk, south of Nantucket and Marthas Vineyard. 



Distribution.— Ivish. seas (Farran, Pearson) ; North Atlantic 

 (Brady); Antarctic Ocean (Wolfenden). 



Color.~T\iQ coloring is very bright and the effect beautiful, as it is 

 one of the most brilliantly colored species of our coast. The longer 

 antennae are colorless, and the end of the -snout is whitish and 

 translucent. Thence the color is yellowish white to one-fourth the 

 length of the anterior segment from its posterior end. Here a light 

 pink begins, which deepens and extends to the hinder end of the 

 thorax and into the abdomen. This is an internal coloring and does 

 not reach the surface. Externally there is another red coloration, a 

 bright, glistening blood red, arranged in bands and spots, the bands 

 consisting of closely joined spots. The genital segment is almost en- 

 tirely made up of this color, the abdomen being white. The red on 

 the upper part of the body is most thickly distributed along the 

 middle of the back from the front of the second segment to the genital 



