124 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 53. 



Total length, 225 mm. Head 7 mm. long, 8 mm. wide, 7 mm. thick. 

 Neck, 110 mm. long, 2.50 mm. in diameter. Genital segment, 75 mm. 

 long, G mm. in diameter. Abdomen, 40 mm. long. Egg strings, 330 

 mm. long. 



{instructus^ arranged in definite order, alluding to the frontal proc- 

 esses. ) 



Remarks. — This species may be recognized by the peculiar pattern 

 in which the frontal processes are arranged and by the two curved 

 horns given off from the posterior margin of the cephalothorax. The 

 long distance between the first and second antennae, and the com- 

 paratively long distance to which the third and fourth legs are re- 

 moved are also characteristic. This is undoubtedly the '''' Penella 

 sp?" described by Brian in his preliminary note on the parasitic 

 copepods taken during the scientific voyages of the Prince of Mo- 

 naco^; his figures, especially of the head and horns, are unmistak- 

 able. This species infests the swordfish together Avith filosa, and has 

 not thus far been found upon any other host. The cysts formed 

 around the head and neck in the tissues of the host are very large, 

 and inside of them there is more or less twisting and flexure. 



While the part of the body outside of the host does not apparently 

 afford as good lodgement for Conchoderma as was the case in filosa^ 

 it does prove attractive to hydroids and algae, and is often very 

 heavily loaded with one or both of them. 



PENNELLA ORTHAGORISCI Wright. 



Pennella orthagorisci Weight, Ann. Mag. Nat. Ilist., set. 4, vol. 5, 1870, 

 p. 43, pi. 1. 



Host and record of specimens. — A single lot of 10 females were 

 obtained from Mola mola at Woods Hole, Massachusetts, and have 

 received Cat. No. 42299, U.S.N.M. 



Specific characters of female. — Wright fully described this species 

 in the reference above given, but he had only two specimens obtained 

 in the harbor of Cork, Ireland. The following notes by Mr. Richard 

 Rathbun upon the 10 specimens obtained at Woods Hole will there- 

 fore be of interest by way of comparison : 



Cephalic horns generally three in number, but sometimes only two, 

 as in Wright's figure; they originate from the base of the cephalic 

 region, close to the neck, and often so exactly between the two that 

 it is difficult to s^y to which they properly belong. When only two 

 they originate much farther apart than in Wriglit's figure, very near 

 or quite at the sides of the head toward the dorsal surface. When 

 three in number the third one springs from the dorsal surface mid- 

 way between the other two, sometimes reduced to a mere knob, at 

 others attaining a length two-thirds that of the lateral horns, but 



»Bull, de rinstlt. oc^anog., No. 110, 1908, p. 0. 



