68 AMEKICAN HVDEOIDS. 



Gonosome. — The gonaiigia are small, regularly oval in outline, somewhat compressed, about 

 one and one-half times as long as wide at greatest diameter and about one and three-fourths 

 times as high as the average hydrotheca. The female gonangia, at least, contain medusae 

 wliich eject their ova into an acrocyst without hberating the medusae. The details of the 

 medusae can not be made out in the specimens. Medusoid characters are much less evident in 

 the male gonangium. 



Distribution. — San Diego, California (Clark) ; Pacific Grove, California (Torrey) ; McMurdo 

 Bay, Antarctic (Hickson and Gravely) . 



Bathymetric distribution 1 to 42 fathoms. 



This species is closely alhed to 0. comfressa from which it is separated by the distinctly 

 dentate margin of the characteristic hydro thecse, and the smaller size and more slender pro- 

 portions of the gonangia. 



Genus GONOTHYR^EA Allman. 

 Gonothyrsea Allman- Ann. Mag. Nat. Hist., ser. 3, vol. 13, 1864, p. 374. 

 The original definition of this genus has not been improved upon by subsequent writers 

 and is as follows: 



Trophosome. — Hydrocaulus branching, rooted by a filiform hydrorhiza; hydrothecse bell-shaped, with entire or 

 serrated margin, and destitute of operculum; tentacula surrounding the base of a large, very contractile metastome. 



Gonosome. — Gonophores adelocodonic. Sporosacs in the form of imperfect medusae (meconidia), can-ying round the 

 rudimental codonostome a circle of filiform tentacula, and, when mature, supported on the summit of the gonangium, 

 where they lie entirely external to its cavity. 



KEY TO AMERICAN SPECIES OF 60NOTHTRJLA. 



Margin with teeth which are squared off at top loveni. 



Teeth sharply pointed gracilis. 



Teeth very shallow clarki. 



nn without teeth inomata. 



GONOTHYR.a;A LOVENI (Allman). 



Plate 17, figs. 1-2. 



Sertularia dichotoma (part) Houttuyn, Natuiu-lyke Historie, 1761-73, vol. 17, p. 565. 



Sertularia conlorta Shaw, Vivarium naturse, etc., 1813, p. 789, pi. 962. 



Campanularia dichotoma Lister, Philos. Trans. Royal Soc, pt. 2, 1834, p. 386. 



Sertularia dichotojna Lister, Philos. Trans. Royal Soc, pt. 2, 1834, p. 372. 



Sertularia geniculata Loven, Bidrag til Kannedomen of Slagtena Campanularia och Syncoryna, 1835, p. 261. 



Campanularia geniculata Loven, Bidrag til Kannedomen of Slagtena Campanularia och Syncoryna, 1835, p. 281. 



Campanularia geniculata van Beneden, M^moire sur les Campanulares de la Cote d'Ostend, 1844, p. 34. 



Campanularia dichotoma van Beneden, Recherches sur I'embryogeuie des Tubulaires, 1844, p. 41. 



Campanularia geniculata Steenstrup, Untersuchungen uber das Vorkommen des Hermaphodistismus in der Natur, 



1846, p. 65. 

 Campanularia geniculata LtJTKEN, Nogle Bemaerkninger om Medusernes Syatematiske, etc., 1850, p. 32. 

 Campanularia geniculata Schultze, Ueber der mannlichen Geschlechtstheile der Campanularia geniculata, 1850, 



p. 52. 

 Campanularia geniculata Gegenbatjer, Zur lehre vom Generationswechsel und der Fortpflanzung bei Medusen und 



Polypen, 1854, p. 163. 

 Campanularia geniculata Lindstrom, Om utwecklingen of Sertularia pumila Linnaeus, 1855, p. 370. 

 Laomedea geniculata Greene, On the Acalephae of the Dublin Coast, 1859, p. 249. 



Campanularia geniculata Sars, M., Bidrag til Kundskaben om middlehavets Littoral-Fauna, 1857, p. 161. 

 Laomedea dichotoma Wright, Observations on Brit. Zooph., 18.58, p. 450. 

 Campanularia dichotoma Wright, Observations on Brit. Zooph., 1858, p. 453. 



Laomedea fiexuosa Allman, Notes on the Hydroid Zooph., Ann. Mag. Nat. Hist., ser. 3, vol. 4, 1859, p. 138. 

 Laomedea loveni Allman, Notes on the Hydroid Zooph., Ann. Mag. Nat. Hist., ser. 3, vol. 4, 1859, p. 138. 

 Laomedea fiexuosa Allman, Additional observations on the reproductive organs in the Hydroid Polypes, 1859, p. 310. 

 Campanularia fiexuosa Allman, Additional observations on the morphology of the reproductive organs of Hydroid 



Polypes, 1859, p. 316. 

 Laomedea dichotoma Sars, M., Ann. Mag. Nat. Hist., ser. 3, vol. 8, 1861, p. 359. 

 Laomedea geniculata Sars, M., Ann. Mag. Nat. Hist., ser. 3, vol. 8, 1861, p. 359. 

 Campanularia loveni Greene, A Manual of the Sub-Kingdom Coelenterata, 1861, p. 44. 



