32 BULLETIN OF THE BUREAU OF FISHERIES. 



ECTOPLEURA L. Agassiz (1S62). 



Ectopleura ochracea A. Agassiz. PL II, tig. 1. 



Ectopleura ochracea A. Agassiz, in I. Agassiz, Contributions Natural History United States, Vol. IV, 1862, p. 343; North 

 American Acalephse, 1865, p. 191. Haeekel, System der Medusen, 1879, p. 22. 



Bell elongate ovoid or pyriform, with thick aboral mesoglea, sides of uniform thickness, exunt- 

 brellar surface with eight meridional bands of nematocysts uniting at the apex. Radial canals 4, 

 narrow, and communicating with a well-defined marginal canal. Tentacles 4, usually lung and fila- 

 mentous, though often coiled and contracted when taken in the tow. Size from 2 to 4 mm. in long 

 diameter, by about half as wide. Manubrium large and flask-shaped. 



Colors. — Manubrium yellowish on base and oral end, the latter often reddish; central portion red- 

 dish to pink. Tentacular bulbs of similar color; ocelli reddish brown. 



Distribution. — Common throughout the region in midsummer. 



HYDRICHTHYS Fewkes (1888). 



Hydrichthys minis Fewkes. 

 Hydrichthys minis Fewkes, Bulletin Museum Comparative Zoology, Vol. XIII, 1888, p. 224. 



Bell oval or subspherical, its outer surface dotted here and there with clusters of nematocysts. 

 Marginal tentacles 4 in adult specimens; only 2 when first liberated; tentacular bulbs reddish in color, 

 but devoid of ocelli. Manubrium cylindrical, rather short; mouth simple. 



( 'olors. — Bulbs of tentacles reddish-brow n; manubrium yellowish t 'ange. 



Dvtfrihiition, — A single record, so far as known to the present writer, that of Fewkes above cited; 

 the medusa taken from a fish at Newport. 



PENNARIA Goldfus (1820). 



Pennaria tiarella Ayres. PI. Ill ". 



Globiceps tiarella Ayres. Proceedings Boston Society of Natural History, Vol. IV, 1852, p. 193. L Agassi \ Contributions to 



the Natural History of the United States, Vol. IV. 1862, p. 344. 

 Eucorym elegans Leidy, Marine Invertebrate- of New Jersey and Rhode Island, 1855, p. i. in Journal of Academy of 



Sciences, Philadelphia. Vol. III. 

 Pennaria tiarella McCrady, in Proceedings of Elliott Society of Natural History, Vol. I. 1857, p. 153. A. Agassiz, North 



American Acalephre, 1865, p. 187. 

 Kalocordyle Han Ha Allman, Monograph of the Gymnoblastic Hydroids, 1871, p. 369. 

 Globiceps liareita Haeekel, System der Medusen, 18711, p. 39. 



Bell high, elliptical or ovoid in outline: size 1.5 mm. high by 0.8 mm. broad. Radial canals 4 

 marked by lines of reddish pigment on the exumbrellar surface; marginal tentacles 4, very rudi- 

 mentary. Manubrium spindle-shaped, about half as long as bell; mouth rudimentary, probably not 

 functional. Gonads borne on manubrium and filling entire bell cavity at maturity. Sexual products 

 discharged at once on liberation of the medusa front the hydroid — indeed, often befon — in many cases 

 the medusa never becoming free, but discharging the eggs or sperms and dying upon the branches. 

 l\ nnaria seems to lie just on the border line between the fixed and free gonophore phases not uncom- 

 mon among the Tubulariidse. I have elsewhere discussed this feature of the species in more detail. 

 (Cf. American Naturalist, Vol. XXXIV. p. 390, el se'q. ) 



( 'olors. — General color, pale rosy pink; manubrium, chocolate-brown, reddish pigment along lines 

 of radial canals. < Iva vary from creamy white to orange. 



Distribution. — General throughout the region in shallower waters: less common from deep waters. 

 One of the commonest of our hydromedusae, and exhibiting in striking way the characteristic alter- 

 nation of generation-. As previously shown ( op. cit.l. Pennaria exhibits interesting seasonal and 

 environmental variations. 



Specimens of /'. gibbosa from Florida and Porto Rico, compared with /'. tiarella, show hardly 

 sufficient differences to warrant specific distinctness 



i Figs 3 and ) drawn from lite by H. B. Bigelov 



