830 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXJII. 



But in the females of Pandarus, Nessipus, and allied genera the 

 claw disappears in the fully developed adult and in its place appears 

 a pair of knob-like protuberances, armed with minute papilla^ or 

 scales which operate like a chela and obtain a hold by pinching a 

 fold of skin between their inner surfaces. 



Sometimes the males are also found with knobs instead of claws; 

 the two occurring interchangeably, even in the same species. 



Either of them give the copepod a firm grasp upon its host and, 

 assisted by the adhesion pads, fasten it securely in place. 



Indeed, it has been the author's experience that living specimens 

 have to be removed with great care in order to avoid breaking their 

 prehensile appendages. On the other hand, Hesse speaks of them 

 in the quotation just given as "insecurely fastened to a skin which is 

 tough and leathery." And he then adds: "They are not slow, 



when taken from the water, to 

 detach themselves and fall to 

 the ground or the bottom of the 

 boat." 



In the experience of the pres- 

 ent author no Pandarid has 

 ever voluntarily detached itself; 

 some have fallen or been rubbed 

 off their host, but only when 

 dead. Many scores of times, 

 after pulling the pound-net at 

 the U. S. Bureau of Fisheries or 

 the Marine Biological Labora- 

 tory at Woods Hole, Massa- 

 chusetts, the sharks obtained, which varied from two or three to 

 twenty-five or more in number, have been thrown on the bottom of 

 the boat and towed from 1 to 3 miles behind a small steamer before 

 being examined. But on reaching the wharf the Pandarid parasites 

 were found still clinging to them, and after careful trial it was decided 

 that so far as sharks are concerned, the chief thing to be gained by 

 going out to the net and removing the parasites on the spot was the 

 chance of keeping them alive a little longer. And here again the 

 experience of the author is different from that of Hesse, who says: 

 "I have been able occasionally to secure them alive, but have not 

 been able to keep them m that condition for any length of time. In 

 tliis they are very different from Oaligus and Trehius, and even from 

 Oecrops and Lsemargus, which I have kept alive for some time." 



If he is speaking of the females this is partially true, and yet the 

 author has repeatedly kept Pandarid females alive for several days. 



Fig. 3. — Ventral surface of first three fairs 

 of swimming legs of echthrogaleus denticula- 



TUS, showing accessory ADHESION PADS. 



