﻿April, 1857.] 



ELLIOTT SOCIETY. 



153 



Distribution. — Mediterranean Sea, Long Island Sound, Charles- 

 ton Harbor. 



PENNARIA TIARELLA, {mihi.\ 

 Syn. Globiceps tiarella. Ayres. loc. cit. 

 Eucoryne elegans. Leidy. loc. cit. 



The form of the bell cylindrical and elongate tapers to a rather 

 blunt apex above. The very elongate digestive trunk reaches 

 rather lower than the vail, and protrudes through its aperture at 

 every contraction of the disk; the cavity of the bell is very narrow, 

 so that in repose its wall is scarcely separated from contact with 

 the surface of the digestive trunk. On the external surface of the 

 disk are marked the four longitudinal lines of red blotches, which lie 

 over the radiate tubes and follow their course, are rather irregular 

 though deep colored, and give a remarkable appearance to the 

 Medusa. Tentacula mere rudimentary knobs, four in number, 

 beneath the four marginal bulbs. The coloration of the digestive 

 trunk is a deep opaque red, and the pigment of the vertical lines 

 on the disk is of the same color. 



The polypidom has already been described by Ayres and 

 Leidy. I can find no difference, either in habit or appearance, 

 between the species of Long Island Sound and the coast of 

 New Jersey, as described and as figured by Leidy, and the 

 species found at low water mark in Charleston harbor. The 

 Medusas are developed between the upper and lower sets of 

 tentacula, and while attached to the stem, contain planules 

 which give them their milky-white opacity mentioned by Leidy. 

 They detach themselves, so far as my observations yet extend, 

 before casting their planules, though this may not be an inva- 

 riable rule. The first efforts of contraction appear to be directed 

 to this result, and the planules when cast are untentaculated 

 round embryos. I have observed the Medusa very apathetic 

 after this, exhibiting contractions of the vail only, and these 

 but three or four in succession, then a pause. This portion of its 

 history was observed on the 14th of August. At a later date, 

 September 16th, I found three specimens of the Medusa free and 

 actively swimming about in my jar. Though these were probably 

 more advanced than that of the former date, the tentacula had not 

 increased in length, nor had ocelli made their appearance. The 

 Medusa, before its liberation from the hydra, being greatly dis- 

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