66 AMEEICAN HYDKOIDS. 



surface being typically campanulate in outline. The margin is always even, never regularly 

 dentated. When the walls are greatly thickened the basal chamber assumes the outline of a 

 bell handle. 



Gonosome. — Gonangia very much compressed laterally, being often as broad as long when 

 viewed from the broad side. The specimens were not in a condition to make a satisfactory 

 study of their internal structure practicable. The writer has seen in other specimens indi- 

 cation of medusfe in the gonangia. Torrey (1902) figures a medusa with 4 tentacles just escaping 

 from the gonangium. Another specimen labeled Shumagin Islands (see plate 11, fig. 10) 

 shows a large medusa with 4 radial canals. 



Distribution. — Shumagin Islands, 6 to 20 fathoms on Laminaria (Clark) ; Orca, Alaska 

 (Nutting); San Diego, Cahfornia (Torrey); Smith Channel, Straits of Magellan (Jjklerhohn) . 



Clark's specimens from Shumagin Islands show gonangia with developing medusae greatly 

 resembUng the figures given by Calkins for his Campanularia caliculata from Puget Sound.' 

 Male gonophores are very much like the figure given by von Lendenfeld for EucopeUa cam- 

 panularia,^ the branched processes of the radial canal showing very plainly. 



ORTHOPYXIS CLYTIOIDES (Lamoiuoux). 



Plate 16, figs. 1, 2. 



Tubularia dytioides Lamouroux, in Freycinet, L. de, Voyage autour du Monde ex6cut6 sur les corvettes de S. M. 



I' Uranie et la Physidcnne, 1824, p; 620. 

 Silicularia dytioides Mbyen, tjber das Leuchten des Meeres, 1834, p. 206. 



Tubularia cydoides Milne Edwards, in Lamarck, Hist. Anim. sans Vert., ed. 2, vol. 2, 1836, p. 135. 

 ? Silicularia gracilis Milne Edwards, in Lamarck, Hist. Anim. sans Vert., ed. 2, vol. 2, 1836, p. 135. 

 Campanularia dytioides Hartlaub, Die Hydroiden der magalhaensischen Region und chilenischen Ktiste, 1905, p. 563. 

 Campanularia dytioides Ritchie, Supplementary Rept. on Hydroids of the Scottish Nat. Antartic Exped., 1909, p. 71, 

 Campanulana dytioides Billard, Revision des Espfeces Types d'Hydroides de la Collection Lamouroux, 1909, p. 311. 



TropJiosome.^ — The colony consists of upright unbranched pedicels growing from a creeping 

 rootstock which forms a reticulate pattern over an alga. The rootstock is smooth and usually 

 runs straight from point to point on the alga, and sends off branches at right angles so that a 

 pattern of wide squares or parallelograms is formed. The rootstocks are thick-walled, leaving 

 but a narrow central tube for the coenosarc, and are pinched at the points of origin of the side 

 branches. The pedicels attain a height of about 3 mm., are rather slender, thick-walled, not 

 regularly annulated except at their distal ends where there are usually 2 to 4 annulations sepa- 

 rated by sharp constrictions. There are always 2 or 3 globular annulations just below the hydro- 

 theca, separated from the latter by a very sharp constriction at wliich point the hydrotheca is 

 very easily broken off. There are almost always several (4-8) regular annulations at the 

 basal end of the pedicels, while the median portion is usually smooth. 



The hydrothecse are campanulate, even-rimmed and thick-waUed, the lower part of the 

 walls being greatly thickened to produce an internal annular shelf forming a diaphragm on 

 which the hydranth rests and dividing off a basal chamber which is better marked than in other 

 species of the genus that I have seen. 



Gonosome. — Unknown. 



Hartlaub says this species can be distinguished from Campanularia Integra and EucopeUa 

 caliculata by the fact that the annulations of the pedicels are straight and not twisted or oblique. 



Distribution. — Azores and Sargasso Sea (Meyen); Straits of Magellan (Hartlaub). All the 

 specimens are on floating algse {Sargassum). 



1 Some Hydroids from Puget Sound, 1896, pi. 2, fig. lie. 

 ^ Ueber Coelenteraten der Sudsee, pi. 31, fig. 24. 



^ Description based on moimted slide of this species kindly loaned the writer by Dr. C. Hartlaub. Specimen from 

 the Straits of Magellan. 



