MKDCS.K OF TIIK WORLD. 



and do not develop into planulse while still attached to the medusa. The entoderm of the 

 stomach and tentacle-bulbs is golden-yellow. This species is found oft" the North Atlantic 

 coasts of France, Great Britain, and Germany. It was taken by Hartlaub at Helgoland, 

 German Ocean, in June, and by Browne in the Firth of Clyde, Scotland, in June and July. 



I found a single mature specimen in the harbor of Eastport, 

 Maine, on September 19, 1898. It appears, therefore, to be 

 widely distributed over the North Atlantic. Pictet, 1 893, states 

 that he identifies the hydroid ol this form from Amboina, 

 Malay Archipelago. 



The hydroid of B. hrittninicn has been commonly called 

 B. ramosum, and has been well described by Van Beneden and 

 Allman. The stems are much branched and are 25 to 75 mm. 

 high; the ultimate branches are for the most part alternate. 

 The hydrorhiza is branched and root-like, the branches not 

 anastomosing. The perisarc of the stems exhibits shallow annu- 

 lations at the origin of the branches. The perisarc extends in 

 a cup-like form over the sides of the hydranths almost to the 

 bases of the tentacles, so that the hydranth may be almost 

 completely withdrawn into the hollow of the cup. There are 

 about 12 tentacles which are filiform and not very long and 

 arise in a single zone at the base of the conical hypostome. 

 The tentacles are carried nearly straight, with every alter- 

 nate one elevated and depressed. The medusa-buds are borne 

 singly on moderately long pedicels which arise from the bases 

 of the hydranths upon the terminal branches of the stems. 

 There are I to 2 medusa-buds at the base of each hydranth. 

 When set free the medusa has a bell higher than a hemisphere, 

 with fairly thick walls. There are 8 marginal tentacles, 2 in 

 each radial cluster, and 4 short-knobbed, oral tentacles. 

 Browne, 1898, had a hydroid of this species from the Eddy- 

 stone, English Channel, which liberated 4,450 medusa; in 3 days. 

 Wiesman, 1883, finds that the germ-cells of both sexes originate in the ectoderm of the 

 manubrium of the budding medusa and they do not wander from their place of origin, hut 

 remain there and become mature in the free-swimming medusa. 



Bougainvillia superciliaris L. Agassiz. 



Plate 17, fig. I. 



Hippocrene bougainvillii, Goi'LD, 1841, Report on Invertebrates of Massachusetts, p. 348. 



Hippocrene superciliaris, AGASSIZ, L., 1849, Mem. Amer. Acad., New Series, vol. 4, p. 250, plates 1-3, 53 figs. STIMPSON, 1853, 



Maine Invert. Grand Manan, p. II. 

 Bougainvillia superciliaris, AGASSIZ, L., 1862, Cont. Nat. Hist. U. S., vol. 4, pp. 289, 291, figs. 37-39; p. 344, plate 27, figs. 1-7. 



AGASSIZ, A., 1862, Proc. Boston Soc. Nat. Hist., vol. 9, p. 97, figs. 24, 25; 1865, North Amer. Acal., p. 153, figs. 232-240. 



VERRIU., 1873, Report Commiss. Fish and Fisheries U. S., for 1871-72, pp. 328, 733, plate 37, fig. 276. 

 Hippocrene superciliaris, HAECKEL, 1879, Syst. der Medusen, p. 92. 

 Bougainvillea superciliaris, WAGNER, 1885, Wirbellosen des Weissen Meeres, p. 73, taf. 2, fign. 5, 8, 9; nan 6, 7. LEVINSEN, 



1893, Vid. Meddel.Nat. For. Kjobenhavn, ser. 5, Bd-4, p. 144. MAAS, 1893, Ergeb. der Plankton Exped., Bd. 2, K. c., 



p. 69. HARTLAI B, 1897, Wissen. Meeresuntersuch. auf Helgoland, Heft. I, Abt. 2, p. 466, taf. xvia, fign. I, 5, 7-9, 12; 



taf. xvii, fig. 3; taf. xvir, fign. 3, 4, 11-13; ta ^- xv ' n R- ' 

 Hippocrene superciliaris, SCHLATER, 1891, Revue des Sci. Naturelles, St. Petersbourg, tome 2, p. 342. BIRULA, 1896, Annuairc 



du Mus. Zool. de 1'Acad. Imperiale des Sci., St. Petersbourg, tome I, No. 4, pp. 330, 339. GRONBERG, 1898, Zoolog. 



Jahrb., Abth. Syst., Bd. ii, p. 462, taf. 27, fign. 5, 6. 

 Hippocrene superciliaris-^ H. aurea, LINKO, 1904,200!. Anzeiger, Bd. 28, p. 216; 1900, Mem. Acad. Sci. St. Petersbourg, 



ser. 8, tome 10, No. 3, p. 6, taf. I, fign. 13-18, taf. z, fign. 19-21 (histology of the ocelli). 

 Bougainvillia superciliaris, HARGITT, 1904, Bull. U. S. Bureau of Fisheries, vol. 24, p. 40, I fig. 

 Bougainvillia superciliaris, NETTING, 1901, Bull. U. S. Fish Commission, vol. 19, pp. 330, 376, fig. 90. 

 Bougainvillea paradoxica, MF.RESCHKOWSKV, 1879, Annals and Mag. Nat. Hist., ser. 5, vol. 3, p. 177, plate 20. 

 (?) Hippocrene bougainvillii, BRANDT, 1834, Recueil Actes seances publiques Acad. Imp. Sci. St. Petersbourg, p. 29 (of the 



"separate"); 1853, Mem. Acad. Imp. Sci. St. Petersbourg, ser. 6, vol. 4, part 2, p. 393, plate 20= Bougainvillea merunsii, 



L. Agassiz, 1862. 



Adult medusa. Bell about 10 mm. in height and about same in diameter. Gelatinous 

 substance very thick, so that bell-cavity is only about half as deep as the bell-height. There 

 are 4 clusters of marginal tentacles which are situated at the bases of the 4 radial-canals. 



FIG. 86. Hydroid of Bougainvillia 

 britannica, after Allman, in Ray 

 Society, 1871-72. 



