Ol'.ELIA (?). n 



tween each pair being cut a trifle deeper than the space between the two 

 teeth of each pair, and a striatum beginning at the centre of each of the 

 deeper indentations of the rim is continued proximally for a third or a half 

 of the length 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, 1 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 Gampanularia (?) spinulosa Bale ! ; Obelia 

 bidentata Clarke 2 ; and 0. bicuspidata Clarke. 2 C. spinulosa is like these speci- 

 mens from Perico Island also in beinsf 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 spinulosa 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 C. 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 C (?) spinulosa. Thornely 3 has described a hydroid Gonothyrea longi- 

 ei/atha, 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, 18S8, p. 756. 

 a Transactions Connecticut Acad. Sci., 3, July, 1S75, p. 58. 

 a A. Willey's Zoological Results, Part 4, Dec, 1899, p. 454. 



