MUSEUM OF COMPARATIVE ZOOLOGY. 85 



directly from the inner wall of the bell cavity, as the larva grows older a rounded 

 protuberance forms in the upper walls of the bell cavity from wliich the pro- 

 boscis hangs. This protuberance, when seen from the side, is hemispherical in 

 shape. It forms, however, by means of mesenteries which join the inner wall 

 of the bell in the four meridians passing through the sense-bodies, four pockets, 

 or blind cavities, enclosed by it and the inner bell walls. These pockets are 

 extensions of the bell cavity into the apical walls of the bell, and are separated 

 from each other on the sides by the mesenteries which join the sides of the 

 proboscis and the inner bell walls. In these recesses transparent globules were 

 observed in several specimens. Two of these are represented in Fig. 5. 



Figs. 2, 3. 



Two small jelly-fishes which are closely related to the above, or are the larva; 

 of a Medusa like Tamoya, Avere found on several excursions in Castle Harbor. 

 They are slightly smaller than the youngest larvce of the above-mentioned 

 Acaleph, and for lack of better knowledge have been provisionally referred to 

 S. punctata. 



The bell walls are thin, rigid, and without chymiferous radial tubes, while 

 the outer surface is destitute of the characteristic cells which have suggested 

 the name imnctata. The proboscis is very slightly developo<l, lesembling a 

 simple muscular layer split off from the inner Avails of the bell below the 

 apex. 



The bell margin bears four tentacles alternating Avith as many sense-bodies, 

 all of which are situated in one and the same plane. The four tentacles are 

 rigid, and crossed by annulations of cells arranged in bands, as in T. punctata. 

 Each otocyst is a simple spherical sac, in Avhich is found an otolith. The 

 style Avhich bears the otolith has Avell-defined pigment spots in its w^alls ; 

 these are probably ocelli. Xo Avell-marked " hood," such as exists in Tamoya, 

 is yet developed. Near the point of attachment of the otocyst, Avhich has no 

 peduncle, to the bell margin, there is a thickening of the bell margin, forming a 

 protuberance on either side of which are small clusters of nematocysts. 



Ectopleura sp. 



Fig. 11. 



A small Medusa, evidently larval, is referred to the genus Ectnpknra. Un- 

 like the young* of E. ochracea A. Ag., it has only tAvo Avell-developed tentacles. 



* Bull. Mas. Comp. Zool., IX. 8. An unknown Tubularian (Fig. 14), probably 

 larval, which Avas unlike any of the species of American genera, was taken at New- 

 port during my work there last summer. Description of a single specimen : — 



Bell colorless, liigh, with thin walls and well-marked apex, crossed by four broad 

 radial tubes ; outer surface irregularly covered with lasso-cells. Tlio tentacles are 

 two in number, and are placed opposite eacli other on the bell margin. Proboscis 

 mounted on a hemispherical projection of the apex of tlie bell into the bell cavity. 

 Stomach diminutive, lips small, smooth, slightly colored. 



