MEIHS/E OK WOODS HULK RKOION. 



41 



tera are concerned, the branching radial canals, perhaps, excepted. As will be noted, its shape, 

 tentacles, ocelli, etc, are all distinctively Anthomedusan, and 1 have therefore ventured to place ii 

 among the Margelida?. When its ontogeny comes to be known a different assignment may be required. 



NEMOPSIS L. Agassiz (1849 . 

 Nemopsis bachei I,. Agassiz. Text cut. 



Nemopsia bachei L. Agassiz, Memoirs American Academy Arts and Sciences, Vol. IV, ls-w, p. 289; Contributions Natural 

 History United Slates, Vol. IV. 1862, p. 345. A. Agassiz, North American Acalepha , 1865, p. 149. 



KemopsU gibbesi McCrady, Proceedings Elliott Society Natural History, Vol. I, 1857, p. 160 Allman, Monograph Gyrmn>- 

 elastic Hydroids, 1871, p. 362. 



Nemnpste bachei Haeckel, System der Medusen, ls7*.t, p. 93. 



This medusa, while similar in general aspects t" the species of Bougainvillia above described, has 

 several very distinctive differences, such as the disposition of the gonads beneath the radial canals, and 

 also the pair of clavate marginal tentacles which arch over the clusters of long tentacles. 



It is specifically distinguished by the height and the thickness of the walls and upper portion of 

 the bell. The marginal tentacles are in 4 clusters, arranged about a 

 bulbous pad, with a distinct series of ocelli at their bases and each cluster 

 with a pairof erect, clavate, tentacular bodies. As in Bougainvillia, the 

 tentacles vary in size and number with age, averaging about 7 or 8 in 

 each cluster in mature specimens, tin- ends usually appearing to have 

 clavate enlargements. Manubrium similar to the species already referred 

 in, mouth with 4 complexly branched tentacles which are capable of great 

 contraction, so that they may become almost indistinguishable. Gonads 

 borne on basal portion of manubrium and in course of development 

 extending beneath the radial canals, almost or quite the entire length in 

 many cases. 



Ontogeny. — Unknown. 



Colors. — Sensory bulbs yellowish orange, gonads yellowish. 



Distribution. — Common throughout the region, ranging in season from 

 June to September. 



STYLACTIS Allman (1871). 



Ni mopsis bacht i. 



Stylactis hooperi Sigerfoos. 

 Stylactis hoopi i i Sigerfoos, American Naturalist, Vol. XXXIII, 1899, p. 802, 



Bell globular, slightly elongate, about 1 mm. in height. Marginal tentacles 8, rudimentary. 

 symmetrically disposed about the margin. Ocelli absent. Manubrium large, devoid of oral tentacles 

 or lobes. Gonads borne in genera] mass about the manubrium; products discharged at once upon 

 liberation of the medusa. 



Ontogeny. — Derived directly from a small hydroid, having its habitat upon the shell of a living 

 snail, TUyanassa obsoleta. 



Distribution. — Originally described from Cold Spring Harbor. Long Island. Likely to lie found 

 within the present region. 



Family CLADOXEMID.-E. 



KEY TO THE GENERA. 



A. Marginal tentacles tour, two rudimentary <" mmaria 



B. Marginal tentacles two Carynitin 



GEMMARIA McCrady (1857). 



Four simple radial canals, at the distal exumbrellar terminus of which are 4 dusters or bands of 

 nematocysts. Marginal tentacles L'. at opposite perradial points, each long and with various knob-like 

 and stalked clusters of nematocysts. 



