80 AMERICAN HYDKOIDS. 



the basal chamber rather deep. The hydrothecte are not so deUcate and are longer than those 

 of Obelia hidentata Clarke which they otherwise resemble. 



Gonosome. — Unlaiown. 



Distribution. — The tyije-locahty is Cumberland Bay, South Georgia. No otlier locality is 

 laiown. 



Bathymetric distribution, 1 to 10 fathoms. 



OBELIA BICUSPIDATA Clark. 



Plate 20, figs. 5-6. 



Obelia bicuspidata+0 . hidentata Clakk, On New and Rare species of Hydroids, Trans. Conn. Acad., vol. 3, 1876, 



p. 58. 

 Obelia bicuspidata-\-0 . hidentata Nutting, Hydroids of the Woods Hole Region, 1901, p. 351. 

 Obelia hidentata Hakgitt, Synopsis N. A. Invert., Amer. Nat., 1901, p. 383. 

 Obelia hidentata J ADERBOLM., Aussereuropaischen Hydroiden, 1905, p. 270. 

 Obelia hidentata Mayee, Medusse of the World, vol. 2, the Hydromedusse, 1910, p. 254. 



Tro'phosome} — Colony 2.1 cm. in height, base lacking. The stem and main branches are 

 strongly fascicled. Branches very irregular in disposition, most of the larger ones springing 

 from one side of what appears to be the main stem. ■ The smaller branches and distal parts of 

 the longer ones are monosiphonic and the branchlets are alternate and bear groups of annu- 

 lations above the origin of the branchlets and pedicels. The pedicels are regularly alternate 

 in position and vary in length from one-quarter to one-half the length of the hydrothecse, the 

 terminal pedicels being still longer. The hydrothec^ are large, long, almost tubular, sometimes 

 3 times as long as broad. The hydro thecal walls show strong longitudinal hnes, as if they were 

 pleated, particularly evident in the distal two-thirds of the hydrotheca. The margin is orna- 

 mented by a circlet of bidentate teeth 14 to 20 in number. The vertical hues pass downward 

 from between these teeth. The diaphragm is low, leaving a small basal chamber. 



Gonosome.- — Not heretofore described. Gonangia borne in the axils of the pedicel, very 

 minute, about half the height of the hydro thecae, obconic in shape with distal end broad and 

 truncated, coUar wanting. The blastostyle bears what appear to be developing medusae of the 

 Obelia type. 



Distribution. — Type-locahty for 0. bicuspidata Clark, Thimble Islands, Long Island Sound; 

 for 0. bidentata Clark, Greenport, Long Island. The species has been reported from near Woods 

 Hole, Massachusetts (Nutting), and from Cape Frio, Brazil (30 fathoms), by Jaderholm. 



These two species 0. bicuspidata and 0. bidentata were described in the same paper by Clark. 

 In the opinion of the writer they are identical and the priority should be given to the first name 

 given by Clark, which is Obelia bicuspidata. 



OBELIA DICHOTOMA (Linnseus). 



Plate 20, fig. 7. 



Serlularia dichotoma Linn.eus, Systema Naturae, ed. 10, 1758, p. 812. 



Sertularia dichotoma (part) Houttuyn, Natuurlyke Historie, vol. 7, 1761-73, p. 565. 



Serlularia dichotoma Linn.«;us, Systema Naturae, ed, 12, 1767, p. 1312. 



Sertularia dichotoma Maratti, De Plantis Zoophytes et Lithophytes, 1776, p. 34. 



Scrtolaria dichotoma Cavolini, Memoria per servire de'.l astoria di Polipi marini, 1785, p. 194. 



Serlularia dichotoma (part) Wileen.s and Hbrbst, in Pallas, Charakteristik der Thierpflanzen, 1787, p. 159. 



Sertularia dicliotoTna Gmelin, in Linnaeus, Systema Naturae, ed. 13, 1788-1893, p. 3855. 



Sertularia dichotoma Berkenhout, Synopsis of Nat. Hist, of Gt. Britain and Ireland, vol. 1, 1795, p. 218. 



Serlularia dichotoma Bosc, Hist. Nat. des Vers, 1802, vol. 3, p. 99. 



Sertularia dichotoma Turton, British Fauna, 1807, p. 215. 



Serlularia dichotoma Jameson, Cat. animals of the Class Vermes, 1811, p. 564. 



Laomedea (sertularia) dichotoma Lamoitroux, Nouveau Bull, des Sci. par la Soc. philomatique, vol. 3, 1812, p. 184. 



' Description of one of Clark's cotypes sent me by Professor Verrill and labeled "Obelia bidentata Clark, Greenport, 

 Long Island, Aug. 5, 1874. Piles of \^'harf." 



^Described from a specimen collected by C. M. Fraser at Beaufort, North Carolina. 



