CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 49 



to study the internal structure of the animals. They also placed too much 

 reliance on external shape, which is not only very variable but is also 

 greatly modified by temporary contractions of the muscles. The color in 

 Beroe also changes with age, the very young animals being spotted, after- 

 wards almost transparent, and finally, when mature, more or less diffusely 

 pigmented. Also specimens from cold waters are apt to be pink, while 

 those from the tropics are apt to be dull, translucent, and milky in hue. 



B. ovata and B. forskali are known from the Mediterranean, and they 

 range widely over the tropical Atlantic and Pacific. B. cucumis is found 

 in the Arctic and Antarctic regions and according to Moser also in the 

 Atlantic, Pacific, and Indian oceans, being cosmopolitan in its wide range. 



Pandora of Eschscholtz and Moser is, I believe, only a common 

 aberration or growth-stage of Beroe in which the 4 subventral rows of 

 combs are longer than the others. Every large swarm of Beroe ovata 

 along our coast contains some half-grown individuals in this stage, but 

 I have never observed this condition in fully-grown animals. The gen- 

 eric name Pandora is preoccupied and can not be applied to ctenophores. 



Kinoshita, 19 10, Centralblatt Physiol., Bd. 24, p. 726, finds that in 

 Beroe and Leucothea the combs are brought to a stand-still by mechanical 

 stimulation of the oral pole, or of the oral-ward part of a section of the 

 animal ; and conversely a stimulation of the aboral pole of a quiet animal 

 sets its cilia into movement, a result which would not follow if we stimu- 

 lated the oral pole. Stimulation increases the rapidity of the waves 

 that course down the rows of combs. 



Beroe ovata Chamisso and Eysenhardt. (Figs. 66, 68 to 75; plates 14 to 16.) 



Beroe. Browne, 1756, The Civil and Natural History of Jamaica, p. 384, Table 

 43, fig. 2; also, Second edition, 1789. 



(?) Beroe albens, Forskal, 1775, Descrip. animal, p. iii. 



Medusa infundibulum, Turton, 1806, Linn6's Sys. Nature, vol. 4, Worms, p. 121. 



Beroe ovata, B. capensis, B. punctata, Chamisso et Eysenhardt, 1821, Nova Acta 

 Acad. Leop. Car., tome 10, pp. 360, 361, Tab. 31. 



Beroe ovata, B. punctata, Eschscholtz, 1829, Syst. der Acalephen, pp. 36, 37. 



Idya mertensii, Mertens, 1833, Mdm. Acad. Sci., St. P6tersbourg, Sci. Math. 

 Phys. et Nat., s^r. 6, tome 2, p. 536, Taf. 13, Fign. 1-4. 



Idyiopsis clarkii, Agassiz, L., i860, Cont. Nat. Hist. U. S., vol. 3, pp. 288. 296; figs, 

 loi, 102. — Agassiz, A., 1865, North American Acalephse, p. 39, figs. 63, 64. 



Idyiopsis affinis. Agassiz, L., i860, Cont. Nat. Hist. U. S., vol. 3, pp. 288, 296. 



Beroe putictata, McCady, 1859, Proc. Elliott, Soc. Nat. Hist., Charleston, vol. i, p. 254. 



Beroe ovata, Chun, 1880, Ctenophoren des Golfes von Neapel, p. 308, Taf. 14, Fign. 

 I, 2; 1898, Plankton-Expedition, Ctenophoren, p. 26. 



Beroe clarkii, Mayer, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 83. 



Beroe ovata, Allman, 1862, Proc. Royal Soc. Edinburgh, vol. 4, p. 519; also, 

 1882, Jour. Linnean Soc. London, vol. 16, p. 8g (development). — Kruken- 

 BERG, 1880, Vergleichend. physiolog. Studien zu Tunis, etc., pp. 1-22. — 

 Graeffe, 1884, Arbeit. Zool. Inst. Wien, Bd. 5, p. 362 (occurrence at Trieste).— 

 Verworn, 1891. Pfluger's Archiv. fiir ges. Physiol., Bd. 50, p. 423, Fign. 

 1-5 (functions of the apical sense-organ). — Nagel, 1893, Pfliiger's Archiv 

 ftir Physiol., Bd. 54, p. 165, Fign. 1-5 (physiology). — Driesch and Morgan, 

 1895, Archiv fiir Entwickelungsmech., Roux, Bd. 2 p. 204. — Zeigler, 1898, 

 Archiv far Entwick.-Mech., Bd. 7, p. 34, Fign. 1-12. — Rhumbler, 1899; 

 Ibid., Bd. 8, p. 187, 28 Fign. (segmentation). — ROmer, 1903, Fauna Arctica, 

 Ctenophoren, p. 84 (list of literature). — Moser, 1903, Ctenophoren der Siboga- 

 Expedition, p. 20 (list of literature). — Samassa, 1892, Archiv ftir mikroskop. 

 Anat., Bd. 40, p. 207, Taf. 8, 9 (histology). — Lojacono, 1908, Joum. Phys. 

 Path. Gen., Paris, tome 10. p. looi (the poison of Beroe). — Moser, 1908, 

 Abhandl. Akad, Mtinchen, Suppl. Bd. i, Abhandl. 4, p. 22. 



Beroe shakespeari, Benham, 1907, Trans New Zeal. Institute, vol. 39, p. 139, pi. 7. 



