34 BULLETIN OF THE BUREAU Ob' FISHERIES. 



development takes place wholly within the tissues of the manubrium, but it is presumably through 

 the penetration of the ectoderm by the spermatozoon, as in several other tubularians. 



Hybocodon is characterized by the presence of 5 meridional lines of orange or pinkish pigment 

 over the exumbrella, two of them arising from the base of the large tentacle. Associated with these 

 bands are batteries of nematocysts. A remarkable feature is the apparently gradual disappearance 

 during late spring and summer of these bands, together with their nematocysts, both being wholly 

 absent in specimens taken in August. 



Colors. — Bell transparent; orange bands over the exumbrella, on base of tentacle, and on knob- at 

 distal ends of radial canals; manubrium similarly colored at its base and oral end. 



Distribution. — Ceneral throughout the region, though usually in greatest abundance within limited 

 anas along the coast. 



Hybocodon pendula (I.. Agassi /.i. PI. II, lig. :;. 



Corymorphapendula L. Agassiz, Contributions to Natural History United States, Vol. IV, 1862, i>. 'J7tv a. Agassiz, North 



American Acalepb.se, 1865, p. 192. 

 Hybocodon pendula Haeckel, System der Medusen, 1879, p. 31; Hargitt, Biological Bulletin, Vol. IV. 1902, p.20. 

 Sfonocaulus pendvlui Allman, Monograph Gymnoblastic Hydroids, 1871, p. 397. 



Bell similar to that of preceding species, though but slightly unsymmetrical, medusa slightly 

 larger; tentacles unequally developed, one rather large, the others much smaller, one being sometimes 

 rudimentary. Manubrium very similar to that of preceding, and with gonads borne on the surface as 

 in the former. 



The hydroid of this medusa I have frequently taken at various places in and about Vineyard Sound 

 and Muskeget Channel, and off Chatham, usually from sandy bottoms and at considerable depths. It 

 is a most beautiful form and lives quite well for a few days in the aquarium. L. Agassi/, stated that its 

 medusa- were not liberated, but A. Agassiz later claimed this to have been a mistake and reported 

 having taken the medusa-, though without direct evidence of their relation to the hydroid. Such has 

 been my own experience. Hydroids with medusa- in all stages of development have often been taken, 

 as have alsi > free medusa-, from waters near where the hydroids were dredged, and at the same time, so 

 that there seems to be little doubt as to their relations. 



Colon. — Very similar to those of //. prolifer, though less bright. 



Family TIARIDiE. 



KEY To THE GENEH V 



A. Marginal tentacles two or four. 



t. Marginal tentacles four; bell with rounded apical projection 'Protiara 



1. Marginal tentacles two; bell with rather sharp apical projection Stomotoca 



B. Marginal tentacles numerous. 



3. Bell with globular apical projection Turru 



1. Bell wit hunt globular apical projection Tarrttopsis 



PROTIARA Haeckel (1879). 



Four perradial tentacles; manubrium with broad sessile base; gonads borne in lour masses on the 

 angles of the manubrium. 



This genus was established by Haeckel to distinguish a medusa of synthetic characters, somewhat 

 intermediate between the Codoniidse and the Tiaridse and indicated by him as the prototype of the 

 latter family. I have elsewhere described briefly a medusa taken in the Woods Hole region which has 

 characters quite similar to tin- genus under consideration. 



>- 

 Protiara haeckeli Hargitt. Text cut. 



Ira haeckeli Hargitt, Biological Bulletin, Vol. IV. 1902, p. 17. 



Bell half-ovoid, with lather elongated apical projection; tentacles four, rather stout, slightly longei 

 than bell, and with enlarged basal bulbs the latter devoid of ocelli ; velum well developed; manubrium 

 prominent, gastric portion quadratic in cross si-cti.ni, and with the milk-white gonads borne on its 



