vol. i] Torrey. — Hydroida of the Pacific Coast. 49 



H. tenellum, but the medusoid gonophores constitute au impor- 

 tant difference in the gonosome. Whether the gonophores are 

 ever liberated as medusae I have no means of knowing at 

 present. Their development to an advanced stage, however, 

 before definitive sex cells appear (they are not present in any of 

 the gonophores) and before the gonotheca containing them has 

 obtained an external opening, is a condition of affairs usually 

 associated with the formation of free medusae — as yet unknown 

 among the Haleciidae. 



The species which Clark ('76) identifies with Halecium 

 tenellum Hineks is in all probability Gampalecium medusiferum. 



Halecium. 



Trophosome. No sareostyles. Other characters those of family. 

 Gonosome. Female blastostyles usually bear two distal hydranths. 

 Gonophores sporosacs. 



Halecium annulatum, sp. no v. 



PI. III. Figs. 30, HI. 



Trophosome. Stems rising from a creeping stolon to a height of 7 mm. ; 

 the longer have two or three regularly alternating branches. Stem and 

 branches more or less regularly annulated throughout. Hydrothecae may be 

 half as deep as broad; margin everted. Sessile hydrothecae alternately on 

 either side of stem or branch; peduncles arising within these carry other 

 hydrothecae which may also give rise to other peduncles. 



Gonosome. Female gonothecae broadly ovate, excessively compressed, 

 with terminal aperture. Single gonophore with numerous ova, surrounded 

 by blastostylar processes reaching to gonothecal wall. 



Distribution. South of Coronado, Cal.; 10-fatb.om line; eel 

 grass. Growing on seaweed. -July C, 1901. 



Halecium kofoidi, sp. no v. 



PI. III. Figs. 32, 33. 

 Trophosome. Colony with a thick trunk from which branches arise irreg- 

 ularly, forming a sparse tuft 11 inches high. The branches may branch 

 again,; from these secondaries the ultimate branchlets grow, alternating 

 regularly on either side of the branch. All branches are divided obliquely 

 into internodes of approximately equal length. Each internode usually 

 bears on a shoulder at its distal end a sessile hydrotheca whieh does not 

 reach beyond the distal internode. Within this hydrotheca another may 

 arise on a short stalk, and within the latter still another on a similar stalk. 

 These stalks are somewhat constricted at the base, and bend away slightly 

 from the stem. Occasionally a stalked hydrotheca arises directly from the 

 internode without the interposition of a sessile hydrotheca. There may be 



