ORTHOCORYNID^. 183 



two parts are simply connected by a narrow tube as long as the diges- 

 tive cavities themselves ; the narrow tube leading to the first digestive 

 cavity extends to the level of the veil ; the radiating tubes and the 

 circular tube are thin, but there is no diflerence in the shape of the 

 bell and of the tentacles of the difierent stages observed. 



Buzzard's Bay, Naushon (A, Agassiz). 



Cat. No. 431), Naushon, July, 1804, A. Agassiz. 



Museum Diagram, No. 20, after A. Agassiz. 



Family ORTHOCORYNIDiE A. Agass. 



I have ventured to separate the genus Zanclea from the Pennaridse, 

 with which it had been associated by McCrady and Professor Agassiz, 

 and to form a new family, on account of the observations of Allman on 

 the development of Zanclea from its Hydroid, Coryne imjiressa Aid. 

 The peculiar form of the Hydrarium, and the still more remarkable 

 characters of the Medusa?, with their tentacles bearing pedunculated 

 knobs of lasso-cells, separate them from the square Medusae of the 

 Pennarida?, while they remind us somewhat of the embryonic stages 

 of Syndictyon. From the resemblance of this Hydroid to Halocharis 

 and to Candelabrum, as well as owing to the close affinities of Cory- 

 nitis to Zanclea, I would propose to unite all these forms into one 

 family, the Orthocorynidne. Does not also the Heterocorclyle Cony- 

 bearei belong to this family ? The great difference between the repro- 

 ductive and the sterile individuals is another example of the polymor- 

 phism so remarkable in Hydractinia. 



CORYNITIS McCr. 



Corynitis McCr. Gymn. Charl. Harbor, p. 29. Medusa. 



Corynitis Agass. Cont. Nat. Hist. U. S., IV. p. 340. 1862. 



Halocharis Agass. Cont. Nat. Hist. U. S., IV. p. 239. 1862. Hydrarium. 



Corynitis Agassizii McCr. 



Corynitis Agassizii McCr. Gymn. Charl. Harbor, p. 30, PI. 9, Figs. 3-8. 



Corynitis Agassizii Agass. Cont. Nat. Hist. U. S., IV. p. 340. 1862. 



Halocharis spiralis Agass. Cont. Nat. Hist. U. S., IV. p. 239, PI. 20, Figs. 10, 10«. 1862 



Charleston, S. C. (McCrady). 



