52 CTENOPHORES OF THE ATLANTIC COAST OP 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 fiir 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. 



Verwom, 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). 



Beroe cucumis Fabricius. (Fig. 67, plate 15; fig. 76, plate 17.) 



Beroe cucumis, Fabricius, 1780, Fauna Gronlandica, No. 353, p. 361. — Esch- 

 scHOLTZ, 1829, Syst. der Acalephen, p. 36. — Sars, M., 1835, Beskriv. og. Jagt- 

 tageker., p. 30, Tab. 6, Fign. i5a-d. — Morch, 1857, Beskriv. af. GrSnland., 

 p. 98. — VanhOffen, 1895, Bibliotheca Zoologica, Heft 20, Lfg. i, pp. 16. 20, 

 21. — Chun, 1898, Ctenophoren der Plankton Expedition, p. 26. — R5mer, 

 1903, Fauna Arctica, Ctenophoren, Bd. 3, p. 81 (full list of literature). — 

 MosER, 1903, Ctenophoren der Szfcoga-Expedition, p. 21. — VanhOffen, 1906, 

 Nordisches Plankton, Ctenophoren, 11, p. 7, Fign. 16, 17. — Browne, 1905, Proc. 

 Royal Soc. Edinburgh, p. 785. — Moser, 1908, Abhandl. Akad., Miinchen, Suppl. 

 Bd. I, 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. Siidpolar-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, Agassiz, L., i860, Cont. Nat. Hist. U. S., vol. 3, pp. 270, 296, plates 

 1, 2. — Packard, A. S., 1863, Canadian Nat. and Geol., vol. 8. — Agassiz, 

 A., 1865, North Amer. Acal., p. 36, figs. 52-62; 1874, Mem. American Acad., 

 vol. 10, No. 3, p. 362, plates i, 2; plate 3, figs. 1-24. — Fewkes, 1884, Mem. 

 Mus. Comp. Zool. at Harvard College, vol. 9, No. 3, figs. 1-7, 10-13, 46, 48-50, 

 pi. IX. 



Beroe roseola, Leidy, 1890, Proc. Acad. Nat. Sci. Philadelphia, p. 341. 



This species attains a length of 60 to 100 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 Beroe 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" 



