NO. 2194. NORTH AMERICAN PARASITIC C0PEP0D8— WILSON. 119 



PENNELLA FILOSA (Linnaeus). 



Plate 15, figs. 125-127 ; plate 16, figs. 128-133 ; plnte 17, figs. 134-139. 



Pennatula filosa Linnaeus, Systema Naturae, 1758, p. 819. 

 Lcniaea cinhosa La Maetini£re, Atlas du Voyage de la Pdrouse, 1798, 



pi. 2. fig. G. 

 PcncUus fllosa Milne Edwards, Hist. Nat. des Crustac^s, 1840, vol. 3, p. 52.3. 



PcneUa filosa Quidor, Deuxieme Expedition Antarctique Frangaise, Char- 

 cot, 1912, pi. 1, figs. 5-8 ; pi. 4, figs. 35, 36. 



PcnneUa filosa Cuvier, R&giie Auimal, 1830, vol. 3, p. 257. — M. T. Thompson, 

 Biological Bulletin, 1905, vol. 8, p. 296, 6 text figs.— Brian, R^sultats 

 Scientifiques Prince de Monaco, fasc. 38, 1912, p. 16, pi. 3, figs. 2-A ; pi. 6, 

 fig. 10. 



PenneUa rubra Brian, Copepodi parassiti del Pesci d'ltalia, 1906, p. 86, pi. 7, 

 fig. 3. 



Ilost and record of specimens. — The following specimens of this 

 parasite appear in the United States National Museum collection; 

 Cat. No. 3155, one female from a swordfish captured off the coast of 

 Nova Scotia; Cat. No. G143, two females from Mola rotunda^ off 

 Marthas Vineyard; Cat. No. 6144, two females from a swordfish, 

 Woods Hole, Massachusetts; Cat. No. 42298, twelve females much 

 infested with barnacles from an unknown locality and host; Cat. 

 No. 42307, seven females from swordfish at Woods Hole; Cat. No. 

 42313, ten females from swordfish, Woods Hole ; Cat. No. 47754, five 

 females from sunfish. Woods Hole, much infested with barnacles; 

 Cat. No. 47755, eight heads only from swordfish. Woods Hole ; Cat. 

 No. 47821, one female from Mola rotunda^ Woods Hole; Cat. No. 

 47822, two females from Tetra2)turus alhidus, north Atlantic. 



jSpecific characters of female. — Cephalothorax subspherical, wider 

 than long, slightly flattened dorsoventrally, and almost squarely 

 truncated at the anterior end, which is covered with short processes. 

 These processes are usually branched like those on a cauliflower, 

 especially around the edges, but some of them are simple. Where 

 the head joins the neck a pair of short, straight, and unbranched 

 horns are given off on the dorsal surface, and there is often a shorter 

 third one between them. 



On the dorsal, lateral, and ventral surfaces of the head, near the 

 beginning of the processes at the anterior end, there are usually sev- 

 eral small knobs, irregularly disposed and never alike in any two 

 specimens. 



Neck comparatively thick, about the same diameter throughout, 

 and considerably shorter than the genital segment. The latter is 

 about twice the diameter of the neck and transversely ridged, in- 

 creasing gradually from the neck and then remaining the same 

 diameter for the rest of its length. 



