Crassicauda crassicauda {Crepl.) and its Hosts. 145 



ledg-e of the Cetacea, and has, at my request, examined the 

 description o£ Rosenthal and Hornschucli and that of 

 ]\I (inter, informs me that, in his opinion, the facts point to 

 the conclusion that the wl)ale in question was a common 

 rorqual {BaJcenoptera pl/t/salus, \j. = B. 77iu s c ul u s, aucU.) and 

 not a blue whale. The main reasons for this conclusion, 

 stated briefly, are : — (1) The general coloration of the body 

 — black above, -white beneath ; (2) the colour (white) of tiie 

 first ninety baleen-plates on the right side (this asymmetrical 

 condition is highly characteristic of the common rorqual) ; 

 (?)) the comparatively small breadth of the baleen-plates ; 



(4) the number of vertebrae (61) and of pairs of ribs (15) ; 



(5) the number of finger-bones ; (6) the figures representing 

 the external appearance of the animal, reproduced by Miinter 

 from drawings made in 1825 (these, in Dr. Ilarmer's opinion, 

 " indicate the common rorqual rather than the blue whale ^') ; 

 (7) the month (April) in which the 1825 whale was stranded. 

 The blue whale seldom appears off the Norwegian coasts 

 before the end of May or beginning of June. 



It is somewhat remarkable tliat Diesing* has recorded 

 the host of Creplin's original material as ^'Bahena borealh,^^ 

 while von Linstow f has included the parasite (the reference 

 being to Creplin's material) among those of Bakcna mysti- 

 cetus, L. It may be supposed that both these records are 

 erroneous; they were doubtless due to the uncertainty 

 existing as to the determination of the 1825 whale. 



In the case of the * Terra Nova' material the host was 

 another baleen whale, Megaptera nodosa, taken off New- 

 Zealand. Mr. J. E. Plamilton, who has been investigatino- 

 various questions connected with whales at the Belmullet 

 Whaling Station, states in his report for 1914 J that he 

 found " Nematode worms of some size " in the urinary 

 vessels of twenty-one finners [B. physalus), in one blue 

 whale {B. musculus), and in the sejhval [B.horealis, Lesson). 

 These worms, Mr. Hamilton considers, are very closely allied 

 to, if not identical with, Crassicauda crossicauda. It is of 

 especial interest to note that they occurred most commonly in 

 B. })Iiysahis, a fact which lends great probability to the view- 

 that the host of the types belonged to that species. 



The parasite evidently has its normal habitat in the urino- 

 genital system of its host. In Creplin's original case the 

 worms were discovered in the corpora cavernosa of the male 



* ' Systema Helmintlium,' 1851, p. 264. 

 t ' Compendium der Helmintliologie,' 1878, p. 61, 

 i British Association Report, 1915, " Report on Belmullet Whaling 

 Station." 



Ann. & Mag. N. Hist. Ser. 8. Vol. xvii. 10 



