vol. i.] Torrey. — Hydremia of the Pacific Coast. 31 



there is in Clava a certain correspondence of methods of regen- 

 eration and normal development. This correspondence is not 

 necessarily true for all hydroids, (e.g., Tubularia, /<.4(>), which 

 makes it important to determine the factors which lie behind the 

 differences wherever they exist. 



Fam. Corynid-e. 



Trophosome. Hydraaths spindle shaped, with scattered capitate tentacles, 

 and a conical proboscis. 



Gonosome. " Fixed sporosacs, or medusre with a very long manubrium, 

 four marginal tentacles and four sense bulbs with eye-spots." Nutting, 

 1901, p. 164. 



Syncoryne. 



Trophosome. Characters of the family. 



Gonosome. "Free medusa' with a very long manubrium, four margina 

 tentacles and four sense bulbs with eye-spots." Nutting, 1901, p. 1G4. 



Syncoryne eximia Allman. 



Conjne eximia, Allman, Ann. N. H., 1859 (3), IV, p. 141. 

 Syncoryne eximia, Allman, Ann. N. H., 1864, (3), XIII, p. 357. Nutting, 

 Proc. Wash. Ac. So., 1901, III, p. 166. 



Distribution . Pacific (Jrove, Cal. Juneau, Al. (Nutting). 

 • it. Britain (Allman). Lofoten Is., Norway (Sars). 

 Fragment of stem. No gouophores. Dec. 1!). 1896. 



Syncoryne mirabilis Ag. 



Conjne mirabilis, Ag., Contra N. H. U. S., 1862, IV, p. 185. 

 Conjne rosaria, A. Ag., 111. Cat., 1865, II, p. 176. 



Distribution. San Francisco Bay, between tides. Atl. U.S. 



(Ag. and Clark). Spitzbergen (Marktanner — Turn.). 



It does not seem to me that a separation of the western rep- 

 resentative of this species from the eastern is advisable. The 

 trophosomes agree in all points, and it is doubtful whether the 

 medusas are distinguishable. 



As Agassiz has said concerning 8. mirabilis, it lives either 

 in the open sea or in brackish water in equal abundance. 

 Corresponding with these extremes of habitat it lives in San 

 Francisco Bay under two forms. The one grow x s at the entrance 

 of the bay, upon rocks which are exposed to the breakers of the 



