OBELIA (?). 11 
tween each pair being cut a trifle deeper than the space between the two 
teeth of each pair, and a striation beginning at the centre of each of the 
deeper indentations of the rim is continued proximally for a third or a half 
of the leneth of the hydrotheca. 
Gonosome : -— Unknown. 
Habitat : — Perico Island. 
The method of reproduction being unknown, makes it impossible to 
determine the generic relations of this species, and because there are 
only a very few specimens, and they so small as to suggest the possi- 
bility of their being young colonies, I do not believe in giving it a specific 
name. There are, so far as I know, three other species which have hy- 
drothecae of a similar shape, with the same arrangement of the teeth in pairs, 
and the same striations. They are Campanularia(?) spinulosa Bale’; Obelia 
bidentata Clarke*; and 0. bicuspidata Clarke.” C. spinulosa is like these speci- 
mens from Perico Island also in being a small form “ about half an inch 
high” and in having the marginal teeth crested, but much more promi- 
nently so than in the Perico specimens. The stem in C spiu/osa exhibits 
the rudiments of a compound or polysiphonic structure, there is more annu- 
lation of the stem, the peduncles are longer and more slender, the hydroth- 
ecae are shorter in proportion to their greatest width, and the teeth are 
shorter than in the specimens from Perico Island. The number of the teeth 
in @. spinulosa is from 20 to 24; in the Perico form, 16 to 18. 
The figure of this Perico form compares very closely with that of 
O. bidentata Clarke, but the latter has a compound stem, attains a height of 
150 mm., and is much branched. Our specimens may be young specimens 
of 0. bidentata, but without more material and a knowledge of the gonosome 
that point cannot be determined. Bale makes the same suggestion in regard 
to his CO. (?) spinulosa. Thornely * has described a hydroid Gonothyrea longr- 
cyatha, from New Britain Island, which also has the teeth in pairs on a cas- 
tellated rim; the striations, however, are wanting. The stem becomes 
compound by the development of stolons from the bases of the peduncles, 
and they grow downward as they do in Bale’s C. (?) spinulosa. Three of these 
campanulate forms with castellated rims and paired teeth are from the 
Pacific Ocean, — Perico Island, New Britain Island, and Australia, — and 
1 Proceedings Linnean Soc. New South Wales, June 27, 1888, p. 756. 
2 Transactions Connecticut Acad. Sci., 3, July, 1875, p. 58. 
8 A. Willey’s Zoological Results, Part 4, Dec., 1899, p. 454. 
