﻿152 



PROCEEDINGS OP THE 



[April, 1857. 



definition, like the small lateral tentacula of Eu-cheilota. I believe 

 that I have not seen the true wall of this pedicle at all, and that the 

 dark irregular line figured is only a sort of granular content of the 

 cells, composing the pedicle. On each of the other two points where 

 tentacula might be expected, there was only a dark colored spot, 

 marking the position. From what has been related of Corynitis, 

 however, it will be seen that it would not be safe to conclude that 

 the species preserves this bi-tentaculate form through life. There 

 was a remarkable tendency to fold these tentacula inwards, so as 

 to bring them within the bell. After a careful search, I deter- 

 mined that the ocelli were entirely wanting, as Gegenbaur also 

 has observed in his more mature Z. costata. 



The few specimens of this species from which the above de- 

 scription was made, were taken during the summer and fall, in 

 the months of June, August and October. 



PENNARIA. Goldfuss. (1820?.) 

 Syn. Globiceps. — Ayres. Proceedings Boston Soc. Nat. Hist., vol. 4, (1852,) p. 193. 

 Eucoryne. — Leidy. Marine Invertebrata of N. Jersey, p. 4, pi. X, ff. 1-5, (1855.) 



The general form of the Medusa is that of a deep bell, with 

 short transverse axis giving an elongated cylindroid figure. Ex- 

 ternal surface ornamented with rows of pigment cells ascending 

 from the marginal bulbs. Digestive trunk elongate, surrounded 

 by the sexual organs. Radiate tubes four, simple. Marginal bulbs 

 large, almost colorless. Ocelli wanting, as in Zanclea. Tentacula, 

 so far as yet known, mere rudimentary tubercles, four in num- 

 ber. Larva, a hydroid having a cylindrical body with two whorls 

 of tentacula, of which those of the double oral whorl are clavate, 

 those of the lower whorl, filiform as in Stauridium, but instead of 

 being limited to four as in that genus, they are numerous in each 

 whorl. The horny polypidom forms a regularly and beautifully 

 branched plume, along the branchlets of which at pretty regular 

 intervals and uniserially, are arranged the individual polyps, each 

 attached to the branchlet by a distinctly annulate pedicle. The 

 Medusa is developed as in Tubularia, between the upper and 

 lower whorls of tentacula, and becomes free. Judging from the 

 condition of the following species, which 'condition is probably 

 the same for the Sertularia pcnnaria of Cavolini, several planules 

 are developed in the cavity of the Medusa-bell during its growth, 

 and are discharged at the time of the Medusa's liberation from its 

 larva. 



