52 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 
power to induce a process of regeneration whereby the complete form 
might be restored. One should consult a review of the work of Driesch 
and Morgan by Roux, 1895 (Roux’s Archiv fir Entwickelungsmechanik 
Bd. 2, p. 448), and also by Chun in the same volume (p. 444), who main- 
tains that the missing parts of these partial embryos will in time regen- 
erate. Probably every one who has studied living ctenophores will agree 
that, while their healing power is remarkable, they appear to have little 
power to regenerate lost parts. 
Verworn, 1891, finds that the concretions of the sense-organ in 
B. ovata are not organs of hearing, but serve to maintain the equilibrium 
and normal position of the body in the water, and should thus be called 
statoliths. (See also Engelmann, 1887, Zool. Anzeig., Jahrg. 10, p. 439.) 
\ The histology of B. ovata is dealt with at length by R. Hertwig, 1880 
(Jena. Zeit. fur Naturw., Bd. 14, pp. 316-457); and by Samassa, 1892 
(Archiv mikroskop. Anat., Bd. 40, pp. 159, 207). 
Beroé cucumis Fabricius. (Fig. 67, plate 15; fig. 76, plate 17.) 
Beroé cucumis, Fazsricius, 1780, Fauna Grénlandica, No. 353, p. 361.—EscuH- 
SCHOLTZ, 1829, Syst. der Acalephen, p. 36.—Sars, M., 1835, Beskriv. og. Jagt- 
tageker., p. 30, Tab. 6, Fign. 15a-d—Morcu, 1857, Beskriv. af. Grénland., 
p. 98.—VANHOFFEN, 1895, Bibliotheca Zoologica, Heft 20, Lig. 1, pp. 16. 20, 
21.—CuHuN, 1898, Ctenophoren der Plankton Expedition, p. 26.—R6MER, 
1903, Fauna Arctica, Ctenophoren, Bd. 3, p. 81 (full list of literature).— 
MOSER, 1903, Ctenophoren der Szboga-Expedition, p. 21.—VANHOFFEN, 1906, 
Nordisches Plankton, Ctenophoren, 11, p. 7, Fign. 16, 17.— BROWNE, 1905, Proc. 
Royal Soc. Edinburgh, p. 785.—MoseEr, 1908, Abhandl. Akad., Mtiinchen, Suppl. 
Bd. 1, Abhandl. 4, p. 23; also, Zool. Anzeiger, Bd. 33, p. 756, 1908, Revue 
Suisse de Zool., tome 16, p. 10 (from Amboina); also, 1909, Ctenophoren der 
deutsch. Stidpolar-Exped., Bd. 11, Zool. 3, pp. 154, 167, 189. 
Idya cucumis, I. borealis, Medea fulgens, M. arctica, Lesson, 1843, Hist. Zooph. 
Acal., pp. 133, 134, 136. 
Idyia roseola, Acassiz, l., 1860, Cont. Nat. Hist. U. S., vol. 3, pp. 270, 296, plates 
1, 2—Packarp, A. S., 1863, Canadian Nat. and Geol., vol. 8—Acassiz, 
A., 1865, North Amer. Acal., p. 36, figs. 52-62; 1874, Mem. American Acad., 
vol. 10, No. 3, p. 362, plates 1, 2; plate 3, figs. 1-24.—FEWKEs, 1884, Mem. 
a Comp. Zool. at Harvard College, vol. 9, No. 3, figs. 1-7, 10-13, 46, 48-50, 
pl. rx. 
Beroé roseola, LEIDY, 1890, Proc. Acad. Nat. Sci. Philadelphia, p. 341. 
This species attains a length of 60 to roo mm. It is miter-shaped 
and the lateral compression is very marked, the broad lateral diameter 
being fully twice the width of the narrow. The 8 rows of cilia extend 
about three-quarters the distance from the apical sense-organ to the 
mouth and each is composed of about 100 combs. It is distinguished 
from Beroé ovata by the fact that the peripheral network does not anas- 
tomose and that none of these vessels join the two lateral paragastric 
canals. There is no ring-canal around the mouth, and the peripheral canal 
systems of the two broad sides are separated one from another. The 
intense pink color of the stellate pigment-cells of the meridional vessels 
and of the circumoral canal is also deeper than in B. ovata. 
This species is abundant along the coast of New England and attains 
a very large size in Halifax Harbor, Nova Scotia, in September. It 
extends along the coast of Greenland, and is common in the Labrador 
current. It is circumpolar in distribution, is abundant in the North 
Sea and off the coast of Scotland, and is identical with “Idyia cyathina”’ 
