54 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 



Moser, 1903 (Ctenophoren der Sz6<3ga-Expedition, pp. 23, 24), has 

 described and figured two closely related varieties of Beroe, one of which, 

 B. pandora, she believes to be identical with Pandora flemingii Esch- 

 scholtz, 1829 (Syst. der Acalephen, p. 39, Taf. 2, Fig. 7). In both of 

 these forms the 4 subventral rows of combs are longer than the sub- 

 tentacular (she reverses the accepted usage of these terms in her de- 

 scription) instead of all 8 rows being of equal length. I doubt whether 

 this is a valid specific distinction, for I have noticed a certain intergrading 

 tendency of young individuals of B. ovata to have relatively short sub- 

 tentacular rows of combs. Such an individual obtained from a swarm 

 of normal B. ovata, with all 8 rows of equal length each to each, is shown 

 in fig. 74, plate 16. When full grown I believe the 8 rows are always 

 practically equal in length each to each. 



The differences between B. pandora and B. pandorino are of such 

 a character that I doubt their validity, bearing in mind the extreme 

 variation in shape of body exhibited by ctenophores of the genus Beroe. 

 Moser, 1908, redescribes this ctenophore from Japan under the name 

 Pandora flemingii (see Abhandl. Akad., Miinchen, 1908, Suppl. Bd. i, 

 Abhandl. 4, p. 32). 



There appear to be but two dominant species of Beroe: B. cucumis 

 of cold water, and B. ovata of warm waters. B. jorskali, B. pandora, etc., 

 are probably only varieties of B. ovata. 



The pink color of the stellate pigment cells of the meridional canals 

 does not appear until the young B. cucumis is about 25 mm. long, and 

 after the side branches have grown out from the sides of the meridional 

 vessels. When young the animal is transparent with a faint yellowish 

 tinge to the canal-system. The side branches do not begin to develop 

 until the animal is 19 mm. long. When about 23 mm. long it begins to 

 lose its transparency, and to assume the translucent milky hue of the 

 adult. 



The young Beroe cucumis devours Pleurohrachia pileus with avidity. 



At Halifax, Nova Scotia, in September when the harbor water 

 ranges from 13° to 15° C, B. cucumis is most active if heated to about 

 18° C, and dies at a temperature between 27.8° and 29.8° C. It would 

 seem therefore that B. cucumis could not survive in the surface waters 

 of the tropics. 



