THE CAMPANULARID^ AND THE BONNEVIELLID^. 93 



The hydrotliecse are almost hemispherical in outline and are quite different from those 

 described by Hartlaub. They are thick-walled and the margin bears a deep sinuation or notch 

 which dips down nearly haK way to the bottom of the hydrotheca in the Challenger specimen. 

 The hydrothecal lumen is much restricted and much too small to accommodate the retracted 

 hydranth. 



Gonosome. — Gonangia borne on the rootstock. The single gonangium on the Ckallenger 

 specimen is very different from the descriptions of Allman and Hartlaub. It is broadly vasiform, 

 with flaring margin, and is borne on a short, thick-walled pedicel. Gonangial contents. — Ova. 

 Hartlaub^ says that the male gonangia a'-e very slender and overtop the female gonangia, their 

 longer stem gradually passmg into the capsule proper, and that the spadLx is strongly branched 

 (in the female). In many gonangia he found free planul^. 



Distribution. — Falkland Islands (Allman); South Terra del Fuego Archipelago, Navarin 

 Island (Michaelsen). 



Genus THAUMANTIAS Eschscholtz.^ 



Trophosome. — Colony simple or branched, hydro thecas campanulate, with a distinct dia- 

 phragm. Proboscis trumpet-shaped. 



Gonosome. — Medusae with 4 radial canals and 4 or more marginal tentacles. Manubriiun 

 with 4 simple lips. No marginal sense-clubs nor lithocysts. 



The trophosome of this genus offers no distinguishing character, being much like that of 

 numerous campanularians. The character of the medusne, particularly the absence of Htho- 

 cysts, offers sufficient groimds for the retention of the genus. 



THAUMANTIAS INCONSPICUA Forbes. 



Plate 25, fig. 9. 



Thawmantias inconspicua Forbes, Monograph of the British Naked-eyed MedusK, 1848, p. 52, pi. 8, figs. 3a, 35 (medusae 



only). 

 Thaumantias inconspicua Wright, Quart. Journ. Micr. Sci., new ser., vol. 2, 1862, p. 221. 

 Thaumantias inconspicua Hincks, British Hydroid Zoophytes, 1868, p. 179. 

 Campanularia inconspicua Calkins, Some Hydroids from Puget Sound, 1899, p. 349. 

 Phialidium hemisphaincum Mayer, The Medusae of the World, vol. 2, 1910, p. 266. 

 Thaumantias inconspicua Fraser, West Coast Hydroids, 1911, p. 40. 



Trophosome.^ — Pedicels growing from a creeping rootstock, together with Lafoea. In 

 some cases these pedicels are branched, but there is no regularity whatever in the mode of 

 branching, and the usual mode of growth is in the form of unbranched pedicels. These are of 

 the ordinary campanularian type, annulated above and below, with a smooth median portion. 

 Hydrothecffi deeply campanulate, the greater part of their sides being parallel and the base 

 evenly rounded. There are usually 7 (7 to 9) well-marked marginal teeth which are rather 

 sharply pomted at the tips, and not rounded as in many forms. "The hydranth rests upon an 

 elevated annular ridge near the outer edge of the diaphragm" (Calkins). 



Gonosome.^ — Gonangia borne on annulated pedicels arising from the creeping rootstock 

 and enlarging to meet the hydrothecal base. The gonangia are oblong ovate in shape and about 

 twice as long as the hydrotheca, with a round terminal aperture without collar. The blasto- 

 style bears four medusae which are hemispherical and show numerous marginal tentacles. 

 The adult medusae, according to Hincks, has 4 radial canals, a short cfuadrate manubrium, and 

 numerous (16 to 40) marginal tentacles, with a tawny sense-bulb at the base of each. There 

 are no Uthocysts. 



^Die Hydroiden der magalhaensischen Region und chilenischen Kuste, 1905, p. 576. 



^ System der Acalephen, Berlin, 1829, p. 102. ' ' Ventriculus simplex, brachiis destitutus, Canali ventriculi quatuor 

 clavati, Cirrhi marginalis pleures basi bulbosi." 



^ Description of specimen collected by C. M. Fraser, San Juan Archipelago, Pacific Coast of British Columbia. 

 The specimens were compared with those collected by Calkins. 



■* Description taken from text and figures given by Calkins in his Some Hydroids from Puget Sound, 1899, p. 349, 

 pi. 2, fig. 8. 



ssges"— 15— 7 



