CTENOPHORA. 87 



be the case in the typical B. cucumis from the Trondhjem Fjord, as I have upon the whole found 

 the same arrangement in all the specimens examined, so far as they were in a condition allowing the 

 examination of, this feature. - I would recall, on this occasion, the observation of L. Agassiz that 

 these cilia are arranged in longitudinal lines, giving the mouth-edge a finely striated appearance (Op. 

 cit. p. 281, PI. I. fig. 2. a, PI. II, fig. 19), as I have also found to be the case. The latter figure also 

 shows the red pigment spots of the mouth-edge to have the shape of fine longitudinal striae, a con- 

 dition which I find to hold good also for those pigment spots occurring inside the band of the sabre- 

 shaped cilia along the wall of the pharyngeal cavity. 



On adopting Chun's suggestion that the sabre-shaped cilia serve the purpose of retaining the 

 prey, in a similar way as the teeth of snakes, Samassa (Histologie d. Ctenophoren, p. 165) concludes 

 that "demnach diirfte ihnen beim erwachsenen Thier active Beweglichkeit kaum zukommen". This 

 suggestion is certainly not right. Chun (loc. cit,) has observed that when the Beroe catches a prey 

 these cilia are very actively moving and "in die Gallerte des Opfers eingeschlagen werden", and I 

 have observed them (under the microscope) to be in a constant, very lively movement, also when they 

 are not about to catch a prey. 



This species most probably possesses the same great power of regeneration as Bolina infun- 

 dibulum. Though I have made no direct experiments in order to ascertain this, I think the conclusion 

 quite justified by the observation of several specimens (in the Trondhjem Fjord) which had all appear- 

 ance of having regenerated different parts of their body. Numerous more or less mutilated speci- 

 mens were often observed, it being sometimes even difficult to find a complete specimen. Such muti- 

 lation being evidently not due to the smooth waters of the fjord, the explanation of this phenomenon 

 is most probably this, that these specimens were damaged by the rough sea outside the fjord, after- 

 wards being carried into the fjord by the tidal current. That all these specimens would regenerate 

 completely I have not the slightest doubt. -- Already M. Sars (Op. cit p. 31) noticed a great percent- 

 age of damaged specimens; he observed rightly that the mutilated specimens are as active in their 

 movements as the undamaged ; but when he suggests that they might continue to live in this condit- 

 ion -- "so little is the mutual connection of the single parts and organs of these low animals" - he 

 is evidently not right, having overlooked the important fact of the regeneration. The same holds 

 good of L. Agassiz (Op. cit. p. 273), who has observed that the large specimens are broken to pieces 

 by the heavy September storms of the American Coasts, from which fact it is concluded that "the 

 adult Idyias, having performed their part in life, break up under the influence of the waning summer; 



while, during the whole winter, the young subside into deep waters, to reappear only with the 



more genial season, when they complete their growth, reproduce their kind, and die in their turn". 

 This certainly looks very plain ; but in our seas at least the large specimens do not disappear with 

 the fall. .1 have observed large specimens in the Gullmar Fjord (at the Zoological Station of Kristine- 

 berg, Sweden) in the month of January. The question of the duration of life in these forms is an 

 unsolved problem, as are so many other points in their biology. 



M. Sars records to have observed a specimen in which the whole aboral portion was lost, so 

 that it resembled a broad ring; however, the specimen appeared to be quite well and comfortable. 

 I have also found such a specimen; on keeping this specimen in a jar together with a Balitia I had 



