58 AMERICAN HYDKOIDS. 



Allman's figure of Campanularia ptychocyathus} (See text figure 22, p. 7.) Hydranths with 

 24 tentacles and a trumpet-shaped proboscis. 



Gonosome. — Gonangia rather short and stout, subcylindrical, annulated throughout, with 

 a very short pedicel and a broad terminal aperture closed by an operculum. Gonangia about 

 1 i times as long as broad and 1 1 times as long as the hydrotheca. Each gonangium contains 

 a single large globular developing medusse with four radiating canals, four tentacles, and devel- 

 oping ovaries. 



The gonosome differs from that of any other Olytia that I have seen. 



Distribution. — Kno:wn only from specimens growing over sargassum weed obtained from 

 the southern edge of the Gulf Stream. 



Type.— Cat. No. 34529, U.S.N.M. 



In Museum of Natural History, State University of Iowa, cotype. 



CLYTU CYLINDRICA L. Agassiz. 



Plate 12, figs. 6, 7. 



Clytia {Platypyxis) cylindrica L. Agassiz, Cont. Nat. Hist. U. S., vol. 4, 1862, p. 306. 



Plalypyxis cylindrica L. Agassiz, Cont. Nat. Hist. U. S., vol. 4, 1862, p. 354. 



Platypyxis cylindrica A. Agassiz, North Amer. Acalephse, 1865, p. 80. 



Clytia cylindrica Nutting, Hydroids of the Woods Hole Regioi}, 1901, p. 343. 



Clytia volubilis (part) Mayer, Medusse of the World, vol. 2, The Hydromedusse, 1910, p. 216. 



TropJiosome.- — Colony consisting of a simple or sparingly branched stem springing from a 

 creeping rootstock and growing over a plumularian hydroid. Total height of longest stems 

 about 5 mm. Branching when present, entirely irregular and straggling. Pedicels varying 

 greatly in length, with middle portion smooth and groups of annulations at the ends. The 

 hydrotheca is tubular or cyhndrical in shape, the basal end rounding rather abruptly to naeet 

 the pedicel. The hydrothecal margin is armed with about 12 sharply pointed teeth. The 

 diaphragm is not well defined in the specimen studied, but appears to be quite low, leaying a small 

 basal chamber. 



Gonosome. — The gonangia are borne on the rootstock and also on the stem near the origins 

 of the pedicels. They are quite slender for this genus, and often have their basal portions 

 curved. When viewed laterally, they are somewhat flattened, so as to be oval rather than 

 round in section, and almost sessile with a few annulations at the extreme base. Their distal 

 end is truncated, sometimes showing a narrow flaring coUar around the margin. Gonangial 

 contents, a blastostyle with a row of developing medusae. Medusse (according to A. Agassiz) 

 much flatter than those of C. joJinstoni. 



Distribution. — Type-locahty, Massachusetts Bay (Agassiz, L.) ; also reported from Nahant, 

 Buzzard's Bay, and Naushon, coast of Massachusetts. 



In the opinion of the writer this species is distinct from C. noliformis (McCrady), the 

 hydro thecse being not "conical" but truly cylindrical. It also appears to differ in the char- 

 acter of the medusae. Brooks ' regards this species as distinct from C. noliformis. 



CLYTIA LONGICYATHA (Allman). 

 Plate 12, figa. 4, 5. 



Obelia longicyatha Axlman, Hydroids of the Gulf Stream, 1877, p. 10. 



Clytia longicyatha Piotet, Hydraires d'Amboine, 1893, p. 28, pi. 2, figs. 22, 23. 



Clytia longicyatha Billard, Travailleur et Talisman, Hydroides, vol. 8, 1907, p. 168. 



This species has not been seen by the author. The following is the original description 

 by Allman: 



' Challenger Reports, Hydroida, pt. 2, pi. 10. 



' Description of a specimen from the Gulf Biological Station, Cameron, Louisiana. 



^ According to Mayer, Medusse of the World, vol. 2, the Hydromedusse, 1910, p. 265. 



