MUSEUM OF COMrARATIVE ZOOLOGY, 159 



tubes, and are four in number. They are long, flexible, Hollow, and with ap- 

 ple-green colored tentacular bulbs. From the ba.se of each tentacle arises a 

 pair (one from each side) of thread-like "spurs," which are generally tightly 

 coiled up, even when the tentacles themselves are extended. These tentacular 

 appendages have a cream color. (For their rektive position see Plate, V. fig. 1.) 

 Intermediate between each pair of tentacles are four rudimentary structures, 

 simple elevations of the bell margin, each of which has thread-like "spurs" 

 similar to those found at the base of the four long tentacles. There are eight 

 otocysts, two between each pair of long tentacles. Each otocyst contains nu- 

 merous otoliths. 



A single specimen of unknown sex was taken at Ne^vport in the middle of 

 August. 



I have proposed the new name E. gracilis, although one of the forms already 

 named may be its young. 



Eucheilota ventricularis, McCkadt. 



Plate V. Figs. 7. 8, 9, 10. 



This species of Eucheilota is not as abundant in Narragansett Bay as E. 

 duodecimalis. The adult has been well described by McCrady, and two young 

 stages are figured by Alexander Agassiz. My figures are of stages intermediate 

 between those given by McCrady and the latter. McCrady's figure of the bell 

 margin of the adult is in some particulars faulty. He figures (Plate XII. 

 fig. 1, 6) a tentacle on the bell rim, which has no lateral cirri. All the tenta- 

 cles have in the adult these characteristic structures. 



The first stage of E. ventricularis which I represent (Plate V. figs. 7, 8) is 

 a little older than one figured by Mr. Agassiz, and has a flat bell with four 

 simple, radial tubes, and eight tentacles, each with a pair of lateral cirri. 

 There are eight otocysts, which alternate in position on the beU margin with 

 the tentacles. The stomach is square in vertical outline, and hangs down 

 about one third the whole depth of the bell cavity. No oral tentacles with 

 knobs, or lasso cells. 



A second and following stage is also figured by me (Plate V. figs. 9, 10). 

 This stage is a little younger than the adult as represented by McCrady. 

 The whole number of tentacles has now increased to sixteen, and the new 

 structures have appeared in such a position on the bell margin that between a 

 primary tentacle and an otocyst there is now placed a single tentacle, so that 

 each otocyst is separated from the adjacent by three tentacles on one side (the 

 medially jilaced of which is a primary tentacle), and by one tentacle, the inter- 

 mediate, on the other. This order in appearance of the tentacles is different 

 from other hydroid medusae. 



The sexual organs are developed on the radial tubes, and are situated mid- 

 way in their course between the stomach and the bell margin. 



The figure which McCrady gives of the adult does not show the true form 



