Mi:i>l>.K UK WOODS HOLE REGION. 47 



Clytia nolliformis (McCrady). 



Campamdaria mlliformU McCrady, in Proceedings Elliott Society of Natural History, V<>1. I, 1857, p. 194. 

 Campanularia vohibUU Leidy, Marine Invertebrates, New Jersey and Rhode Island. 1855, p. 6. 

 chit in cylindrical I. Agassiz, Contributions to Natural History of United States, Vol. IV. 1862, p. sot 

 Platypixis cylindrica \. Agassiz, North American Acaleph&, 1865, p. so. 

 Epenthcsw bicoplwra Haeckel, System der Medusen, 1879, p. 1st. 



This medusa resembles the preceding species so closely in most respects that Haeckel lias included 

 both under liis Erpenthem bieophora, an. I it seems likely that, they are identical. Only occasionally 

 have I taken a specimen that seemed to differ sufficiently to warrant separate classification, though 

 the hydroids seem to he fairly distinct. 



Distribution as of preceding. 



TIM A Eschscholtz | 1829). 



Tima formosa I.. Agassiz. P. IV, fig. 2. 



Timaformom I.. Agassiz, Contributions t<> Natural History of United States, Vol. IV, 1862, p. 362. A. Agassiz, North American 

 Icalephse, 1865, p. lis. Haeckel, System der Medusen, 1879, p. 205. Fewkes, Bulletin Museum Comparative 

 Zoology, Vol. VIII, 1881, p. l">7. 



This splendid medusa, one of our most beautiful eucopids, has a bell-shaped umbrella about as 

 high as broad. Size in maturity about 50 to 60 mm. Body of hell rather thick and heavy, particu- 

 larly in aboral region. Marginal tentacles numerous, with bulbous bases. Manubrium long, capable 

 of protrusion beyond the velum, though usually about on a level therewith. Radial canals 4. rather 



wide, with gonads extending the entire length and downward upon tl longated peduncle of the 



manubrium. Mouth with 4 fimbriated eversible lobes. Otocysts numerous and symmetrically dis- 

 tributed about the margin, each containing several otoliths. 



Fewkes has called attention (Bulletin .Museum Comparative, Zoology, Vol. VIII, p. 157) to the fact 

 that specimens are often devoid of the gastric and oral portions of the manubrium. I have frequently 

 noted tin' same thing, and have suspected that it might be due to voracious fishes, some of which are 

 known to feed upon the oral lobes, etc., of the Scyphomedusae. Whatever the cause, it seems to prove 

 of small inconvenience to the medusa, as the organ is soon regenerated. 



Ontogeny. — Tl ntogeny of Tima has been traced by A. Agassiz (.of. North American Acaiephse, 



p. 115), who .lias reared the hydroid from the eggs discharged by the medusa' in aquaria. The 

 characteristic phases of development, through planulae to polyps and hydroid colonies, occupied some 

 six months, at the end of which the colonies were very minute tufts, barely visible to the naked eye. 



Colors. — While the bell is quite transparent, the milk-white gonads and mouth lobes render the 

 medusa very conspicuous. The tentacles also are white, with a delicate rosy pink in many specimens. 



Ihxiril'iilimi. — Kather ireneiiil throughout the region — Cape Cod, Vineyard Sound, Woods Hole, 

 Buzzards Bay, Newport, etc. I have taken the species only during early sprine; — April and May. It 

 has been reported by Agassiz in March, June, October, and December. Facts seem to indicate the 

 sexual season as rather distinctively spring. 



OBELIA Peron & Lesueur I 1809). 



The genus Obelia, as at present defined by most authors, is much more comprehensive than was 

 understood by Forbes. McCrady, and Agassi/.. As now constituted it comprises medusae having the 

 following characteristics: 



Eight adradial otocysts. which are borne on the inward projecting bases of the marginal tentacles 

 of that region; marginal tentacles numerous. 12 to 24, or even loo or more. Velum rudimentary, bell 

 flat ami freely eversibJV, the medusae often swimming more or less freely in that condition." 



The extremely variable stage of development at which the medusae leave the gonothecae, some- 

 times with 12, 16, 24, or even 4s tentacles, s etimes with the gonads already well developed, 



sometimes without any traces of them, render very difficult any certain determination of species; and 

 the same variable tendencies of the hydroid stocks but add to the difficulties of the problem. Hence, 

 in comparatively few cases max' we feel even a reasonable assurance that the species usually recognized 

 as distinct are entitled to that rank. 



" As \\ ill be noted, this definition includes what by earlier writers were recognized us the genera of Eucope and Obelia, 

 chiefly. 



