76 University of California Publications. [zoology. 



side of the stem, one from the distal end of each internode. There are four 

 to seven hydrotheeae in each hydrocladium. Thecate alternate with non- 

 thecate internodes, the basal internodes being non-thecate. The nodal 

 joints are alternately transverse and oblique, beginning with the basal joint. 

 The thecate are less than twice the length of the non-thecate internodes. 



Each hydrotheca rests on a swelling of the proximal portion of the inter- 

 node. In profile the outer edge is straight, forming an angle of forty-five 

 degrees with the axis of the hydrocladium. The inner edge is free for a 

 distance equalling more than half the length of the outer edge, and while 

 approximately parallel to the latter, flares slightly near the theca-mouth. 

 It reaches the level of the distal extremity of the internode. 



The hydrotheca is laterally compressed, the sides straight and diverging 

 slightly from a narrow base to the mouth, which is broadly oval with smooth 

 margin. 



Each internode has a septal ridge near each end : the distal ridge on the 

 hydrotheeate internode is less conspicuous than the others, which are 

 moderate. 



A single nematophore is borne on each internode of the stem on the side 

 opposite the origin of tne hydrocladium. Two nematophores occur in each 

 axil. Each hydrocladial non-thecate internode bears a single mesial 

 nematophore; each thecate internode bears one mesial nematophore just 

 below the point at which the hydrotheca becomes free from the hydrocladium. 



The perisarc of the stem is thick and brown ; that of the hydrocladia is 

 delicate and colorless. 



Gonosome. Male gonophores small, ovate, attached by very short 

 peduncles between the nematophores in the axils of the stem or branches, one 

 to an axil. Chitinous investment very thin. 



Distribution. San Diego (15-25 fathoms) and Long Beach 

 (5-13 fathoms), Cal., on rocky and sandy bottoms. June and 

 •Inly, 1901. 



Plumularia goodei Nutting. 



PI. X. Figs. 98. PI. XI. Figs, 99, 100. 



Plumularia goodei, Nutting, Am. Hydr., Pt. I., Special Bull. U. S. Nat. 

 Mus., 1900, p. 64. 



Distribution. Pacific Grove, Cal., shore. Santa Barbara 

 Cal., outside reefs (Nutting). 



The gonosome is present (July 25, 1899), and is remarkable 

 for the fact that the gonothecae take the places of hydrotheeae. 

 They are borne near the base of the stem or on the hydrorhiza. 

 There are no traces of regeneration. Apparently a bud which 

 would ordinarily become a hydrocladium may change its func- 

 tion under the influence of appropriate stimuli. 



There are not always two hydrocladia to an internode of the 



