CORYNITIS AGASSIZII. 2S7 



*^* CouTNiTis Agassizii, M' Crudij. 



CoRYNiTis Agassizii, — McCrady, G3'irinoplitlialmata of Charleston IIarl)oiir, p. 133, pi. ix, 



figs. 3 — -8. Agassi::, Coutr. Nat. Hist. U.S., vol. iv, 

 p. 340. 



Halocharis spiralis, — Aytissiz, Contr. Nat. Hist. U.S., vol. iv, p. 239, pi. xx, figs. 10 — 10 c. 



TROPHOSOME. — Hydhanth, when extended, liaving the form of a slender 

 cylinder, with the spirally arranged tentacles successively increasing in size from below 

 upwards. 



GONOSOME. — GoNOPHORES borne among the lower tentacles, or just below them. 

 Medusa, when mature, conico-campanulate about three tenths of an inch in height ; 

 umbrella wall set witli scattered clusters of thread-cells, and with its summit very 

 thick ; marginal tentacles thick, and nodulated with large pads of thread-cells, 

 generative elements occupying about the proximal two thirds of the walls of the 

 manubrium, which is thence continued as a more contracted tube towards the obscurely 

 lobed mouth. 



Colour of mature medusa. — IManuhriuiu deep red, with the generative masses in its walls of 

 a rich orange; basal bulbs and claviform terminations of marginal tentacles red. 



Habitat. — " Growing on sponges a little above dead low water mark." — McCrady. 

 Bathi/mt'trical distribution. — Laminarian zone. 

 Localities. — Charleston, South Carolina ; McCrady. 



The scattered tentacles of the hydranth assume in this species a more decided approacli to a 

 spiral arrangement than is generally met with in the members of its family. 



The trophosome has been described by both McCrady and Agassiz. McCrady has further 

 shown that the medusa, while still young, has only two marginal tentacles, and that at this period 

 its umbrella walls are thin, and the overarched spaces in the roof of the umbrella cavity are absent. 

 These overarched spaces are very striking in the fully developed medusa, and the manulu-ium has 

 then the appearance of being suspended from them in such a way as to have led McCrady to 

 compare it to " one of the massive pendants hanging from a gothic ceiling." 



While there is every reason to believe that McCrady is right in referring to his corynoid 

 trophosome the adult medusa whose description he has given, we must not lose sight of the fact 

 that he has not traced it by continuous observation to the bitentacular form which the medusa 

 presents whUe still attached to the trophosome ; the evidence of identity being afforded by what 

 he seems with justice to regard as intermediate stages of development, but which were seen onlv 

 in specimens captured in a state of freedom in the open sea. 



