242 ALLEN: NEW ENGLAND WHALEBONE WHALES. 



Enemies and Parasites. 



Nothing is known of the enemies of this species or of the natural causes that act to keep its 

 numbers in check. No doubt the Killer Whale occasionally troubles it, but no record is known 

 to me that would prove this. 



Sundry parasitic crustaceans and worms are known from this whale, but it does not sup- 

 port barnacles. CoUett reports what were probably Penellae attached to the edges of both 

 flukes, but he did not personally examine them. These parasites Andrews (1916) has now 

 shown to be the cause of the oval whitish marks described on the body of this whale. The cope- 

 pod Balaenophilus unisetus was first found in this whale by Collett. It infests the whalebone 

 plates to which both the larvae and adults cling in thousands. Figures are given of both 

 stages in the Proceedings of the Zoological Society of London, 1886, p. 257. 



Morch (1911, p. 668) writes of a Rudolphi's Rorqual killed in 1906 at the Shetlands, which 

 had the front end of its lower jaw deformed, and so afforded a foothold for a colony of the 

 stalked barnacle, Conchoderma auritum. This is exceptional, however, for under normal con- 

 ditions this whale does not harbor barnacles. 



Of internal parasites, Collett found two sorts of intestinal worms, one of which appears 

 to be identical with Echinorhynchus porrigens, and has also been recorded by Borgstrom from 

 this whale. The other Collett describes as a new species, E. ruber, but it has been shown that 

 it is the same as E. turbinella Diesing. This latter varies in size according to the degree of 

 maturity up to about 25 mm. in length, is transparent when young but bright red when full 

 grown. E. porrigens is also orange red in color. These parasites attach themselves by a head, 

 thickly studded with spines, to the inner wall of the small intestine, and absorb their nourish- 

 ment from the digesting fo'od. They pass only a part of their life as parasites of the whale, 

 for the first stage is lived probably within some crustacean on which the whale feeds. Figures 

 of these two Echinorhynchi are given by Borgstrom (1892). 



Two species of tape worm are known to occur in the intestinal canal of Rudolphi's Whale. 

 Both were described by Lonnberg (1892) from specimens collected at a whahng station in 

 Finmark. The first, Boihriocephalus balaenopterae, is made the type of a new subgenus Dip- 

 logonoporus. Its scolex or sucking disk by which it attaches itself to the intestinal wall, is 

 flattened from side to side, with a sucker, shaped in outline like a tennis racquet. The second 

 species, Tetrabothrium affine, has a curiously four-parted scolex of four round petal-like disks. 

 It is allied to a species found in the large shark, Lamna, 



