MEiH'S.K <>K Woods HOLE REGION. 45 



Family CANNOTID/C. 



Radial eauals with numerous, pinnate, blind diverticula Ptycho 



PTYCHOGENA A. Agassiz i L865). 

 Ptychogena lactea A. Agassiz. 

 Pttfclioffena lactea A. Agassiz, North American Acalephje, 1865, p. 137. Haeckel, System 'h-r Medusen, 1879, p. 117. 



Bell dome-shaped, about twice as broad as high, with rather thick walls; marginal tentacles 

 numerous and filamentous; radial canals 4, lateral walls with numerous pouch-like diverticula: gonads 

 variously folded and disposed beneath the canals; gastric cavity very flat, quadrate in form; mouth 



large, but devoid of definite lobes or lips. The i lusa seems wholly devoid of sensory organs of any 



sort. 



According to Agassiz, from whose account this description has been condensed, this is a deep-sea 

 form, seldom coming to the surface, and when doing so apparently killed by the action of the light. 

 i mtogeny unknown. 



Colors. — Gonads, radial canals, and tentacles milk white. 



Distribution. — Massachusetts Bay. The occurrence of this species within the immediate region of 

 \V Is Hole has not been reported, so far as 1 am aware, though it is likely to be taken at almost any 



time. 



Family EUCOPID^E. 



KEY TO THE GENERA. 



A. Marginal tentacles 1. sometimes with lateral cirri. 



1. Manubrium very long, extending beyond velum E'<tn„,> 



'J. Manubrium short, tentacles with lateral basal cirri Euchcilola 



3. Manubrium short, tentacles devoid of basal cirri Clytia (juv.) 



B. Marginal tentacles If, or more. 



4. Manubrium long, bell hemispherical Tima 



5. Manubrium short, bell discoid, otocysts on bases of tentacles Obt I'm 



t">. Manubrium short, bell hemispherical, otocysts between bases of tentacle- ClytiaOT EpentkesiH 



7. Manubrium short, oral lips variously fimbriated Tiaropsis 



s. Manubrium short, 12 otocysts, tentacles with interposed cirri Phialu 



9 Manubrium short quadrate, 16 marginal tentacles, with 16 interposed otocysts Epenlhesis 



10. Manubrium short, oral lobes plain, tentacles more than lit. two otocysts between each pair Oceania 



EUTIMA McCrady i 1857). 



Eutima mira Met radv. PL [V, lie;. 1. 



Eutima mira McCrady, Proceedings Elliott Society Natural History, Vol. I. 1857, p. 190. L. Agassiz, ContributioicvNatural 

 History L'nited states. Vol. IV. 1862, p. 360. A. Agassiz, North American Acalephae, 1865, p. lit',. Haeckel 

 System der Medusen, 1879, p. 191. 



Medusa low, hell-shaped, about t w ice as wide as high, walls of bell very flabby, collapsing almost 

 at once on being taken from the water. Size of adult 1"> to 20 hum. in wide diameter. Marginal ten- 

 tacles 4, very long and tapering to mere threads; each has a larger base with a pair of distinct cirri, 

 though these are often so closely coiled a- to escape attention. The velum is extremely delicate and 

 perhaps little functional as an organ of locomotion, which is chiefly accomplished by rhythmic con- 

 tractions of the entire bell. The manubrium is very long and pendulous, extending beyond the bell- 

 margin two ,,r three times its height. There is a long gelatinous peduncle, only the distal tilth consti- 

 tuting the gastric portion. The mouth is 4-lobed with strongly eversible lips, which form a disk-like 

 organ not unlike the sucking disk of a leech. <b>nads are borne along the median portion of the 

 canals. The 8 otocysts an- disposed about the margin of the bell, each containing several otoliths 

 arranged in the form of crescents. Within each marginal quadrant there are also :'. rudimentary ten- 

 tacles, each with its pair of cirri, which tire also rudimentary, and slight swellings which appear to be 

 of similar character. < ratogeny unknown. 



' 'olors. — Bell very transparent, basal portion of tentacles pale green by reflected light, but a beauti- 

 ful rose color by transmitted light, tin interesting character which is possessed by many other medu-.c 

 The distal portion of the manubrium is also greenish with a pale pinkish hue, and the same color 

 though less distinct, is found in the gonads. 



Distribution. — Very common at Wood- Hole and in Vineyard Sound .luring August. 



