256 MR. R. COLLEXr ON BAL.ENOPIKRA BOREALIS. [Feb. 2, 



by myself; and upon inquiry amongst the whalers, I. was in- 

 formed that only Capt. Bryde has noticed such parasites on a 

 single individual captured off Vardo in July. As no specimen has 

 been preserved, it cannot be stated whether they were Crustaceans 

 (Pennellida3?), Biscophora, or other forms. They were worm-like 

 animals, about 50 millim. long, and were attached to the edges of botii 

 flukes (caudal lobes), where they formed a row of free hanging threads. 

 Some were also attached to the upper surface of the flukes. 



In a set of baleen-plates belonging to one specimen, and brought 

 to the University Museum in Ciiristiania from Sorvaer (Mammerfest) 

 in 1883 by Dr. Guldberg, most of the plates are infested on both 

 sides with innumerable specimens of Balanophilus uniselus (figs. A, 

 B, C, D), a Copepodous crustacean of the subfamily Harpacticinae, 

 described by Aurivillius in a pamjjhlet ])ul)lished in Stockholm in 1 879, 

 and discovered by him on the baleen-plates of a specimen of BaUe- 

 noptera sibbaldi caught at Vadsii in July 1877. In 1884, Mr. A. 

 Heneage Cocks found this parasite on a specimen of the same whale 

 at Sorvaer, near Hammerfest (' Zoologist,' 1885, p. 135). So far as 

 I know, it has never been found by other observers. Its occurrence on 

 Balcenopteru borealis is therefore of interest'. The fully developed 

 specimens (figs. A, B) can only with difficulty be recognized in 

 their dry state ; but tlie larvoe in their 2\"aupliiis-Bla'^e (figs- C, D), 

 which are attached to the plates in myriads, still retain most of their 

 original form and appearance. 



These two parasites a[)pear therefore to be of very rare occurrence. 

 However, the intestines of all the specimens that I examined, inclu- 

 ding those which I found on the beach, were, without exception, 

 filled with thousands of Echinurhijnchi, belonging to two diti'erent 

 species. 



One of these, which was very much less numerous than the other, 

 seemed to resemble very closely E. porrii/ens, Rud. Its length was 

 lUO millim. The rostellum was unarmed, the neck long, and the 

 body formed an even continuation of the neck. As I unfortunately 

 only brought one perfect specimen away with me, and as this has 

 the proboscis half retracted, it cannot be decided with certainty 

 whether the species is actually identical with E. porrigens. 



The other species appeared in all the specimens examined, and in 

 such vast numbers that in some places there weie tiiree or four upon 

 each scpiareinch, and they moreover thickly covered the inner coating 

 of the intestines wherever an incision was made. The smallest speci- 

 menswerethin, semi-transparent, and immature; their length wasabout 

 10 millim., the breadth 2 millim. From these up to the full-grown 

 specimens, the length of which was about 25 millim., there were all 

 gradations of size. While the majority of the specimens were of a 

 white colour, the fully adult were of an intense led, as if their 

 integument were impregnated with the colour of the red Crustaceans, 

 which are the principal food of their hosts. The species to which 

 it approaches nearest is E. brevicoUis, described by Malm iu 18()7, 



1 I sent some of the speciuiens to Dr. Aui-ivilliiis, and he has confirmed 

 iLeir identification with the species found on the Blue Wiiale {B. sibbaldi). 



