346 BULLETIN OF THE BUREAU OF FISHERIES. 



Key to Genera of the Syncorynid/E Found in the Beaufort Region. 



A. Chitinous perisarc absent or slightly developed. Hydranths elongated with the stem shorter than 



the hydranth or absent Gemmaria. 



B. Chitinous perisarc well developed. Hydranth body shorter than the stem Syncoryne. 



Genus GEMMARIA. 



Trophosome. — Perisarc absent or slightly developed ; colony consists of a single 

 elongated hydranth growing from a stolon; short capitate tentacles scattered over 

 the whole body of the hydranth. 



Gonosome. — Gonophores producing medusae with two of the tentacles rudi- 

 mentary, the other two well developed and supplied with stalked bodies espe- 

 cially well provided with nematocysts. 



Fig. 2. — Gemmaria cos- 

 tata (Gegenbaur). 



? Gemmaria costata (Gegenbaur). 



Zandea costata Gegenbaur, Zeit. fiir Wissen. Zool , bd. vm, 1S56, p. 329. 

 Gemmaria gemmosa Mayer, BuU. Mus. Conip. Zool., Harvard, 1900, p. 35. 

 Gemmaria coi/a/a Mayer, The Hydromedusae, vol. I, 1910. P- 87. 



Trophosome. — Hydranth elongated, supported by a short pedicel 

 provided with an annulated perisarc. The perisarc of the stolon is 

 not annulated. Tentacles are arranged in numerous fairly definite 

 whorls. 



Gonosome. — Gonophores growing from the hydranth body near 

 the proximal tentacles. 



Color. — Perisarc opaque yellow, hydranths pale red. 



Distribution. — On sargassum collected on the seaward side of Bogue 

 Bank. 



There has been much discussion regarding Gemmaria as to whether 

 it is a genus distinct from Zanclea, but all such discussion has been 

 from the medusa standpoint. As all the hydroids so far described 

 have been called Gemmaria I have used that name. Mayer, who first 

 described and figured this hydroid, confused it, at that time, with 

 Gemmaria gemmosa McCrady, but later recognized the difference. 

 This latter species has also given rise to much confusion, being de- 

 scribed by various authors as Corynitis agassizii and Halocharis spiralis. 

 Hargitt finally cleared up the matter by showing it to be the same 

 species as Halocharis spiralis Agassiz and entirely different from 

 Corynitis agassizii McCrady." 



Gemmaria costata resembles G. gemmosa very much, but can 

 readily be distinguished from it by the short stalk of the hydranth 

 that is supported by the strongly annulated perisarc. G. gemmosa has 

 no pedicel and hence no perisarc except on the stolon. I have made 

 this note because, tliough I did not find G. gemmosa, it is quite pos- 

 sible that it grows in the vicinity, since it is plentiful at Woods Hole 

 and was found as far south as Charleston by McCrady, who first de- 

 scribed it. 



Genus SYNCORYNE. 



Fig. 3. — Syncorytie mirabilis (Agassiz). 



Trophosome. — Colony simple or slightly branched; perisarc well developed; tentacles stout, very 

 strongly capitate. 



Gonosome. — Gonophores usually few in number; medusae with four rudimentary tentacles. 



a Biological Bulletin, 1908, p. 100. 



