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Show 256 MR. R. COLLETT ON BAL^ENOPl'ERA BOREALIS. [Feb. 2, by myself; and upon inquiry amongst the whalers, I was informed 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 1), Discoyhora, or other forms. They were worm-like animals, about 50 millim. long, and were attached to the edges of both flukes (caudal lobes), where they formed a rowof 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 Christiania from Sorvasr (Hammerfest) in 1883 by Dr. Gruldberg, most of the plates are infested on both sides with innumerable specimens of Baleenophilus uniselus (figs. A, B, C, D ) , a Copepodous crustacean of the subfamily Harpacticinae, described by Aurivillius in a pamphlet published in Stockholm in 1879, and discovered by him on the baleen-plates of a specimen of Bala?- noptera sibbaldi caught at Vadso in July 1877- In 1884, Mr. A. Heneage Cocks found this parasite on a specimen of the same whale at Sorveer, near Hammerfest (' Zoologist,' 1885, p. 135). So far as I know, it has never been found by other observers. Its occurrence on Balaenoptera borealis is therefore of interest1. The fully developed specimens (figs. A, B) can only with difficulty be recognized in their dry state; but the larvae in their Nauplius-stage (figs. C, D), which are attached to the plates in myriads, still retain most of their original form and appearance. These two parasites appear therefore to be of very rare occurrence. However, the intestines of all the specimens that 1 examined, including those which 1 found on the beach, were, without exception, filled with thousands of Echinorhynchi, belonging to two different species. One of these, which was very much less numerous than the other, seemed to resemble very closely E. porriyens, Rud. Its length was 100 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. porriyens. The other species appeared in all the specimens examined, and in such vast numbers that in some [daces there were three or four upon each square inch, and they moreover thickly covered the inner coating of the intestines wherever an incision was made. The smallest specimens werethin, 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 red, 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. brevicollis, described by Malm in 1867, 1 I sent some of the specimens to Dr. Aurivillius, and he has confirmed their identification with the species found on the Blue Whale (B. sibbaldi). |
