CALKINS: SOME HYDROIDS FROM PUGET SOUND. 
355 
15. Obelia surcularis sp. nov. PL 3, figs. 14, 14a, 14b. 
PI. 6 , fig. 14c. 
Trophosome. Tlie hydrocaulus is erect, and borne on a creeping 
and branched hydrorhiza. There is never more than one branching 
primary stem. The brandies are regularly alternate, turned 
upwards, and generally end in long filiform tendrils slightly 
/ c *■, ~ 
expanded at the extremity and bearing, in some cases, one or two 
hydrotliecae. Six to eight annulations are found at the base of the 
main stem, three or four above each branch. The stem of the 
liydrotheca is often ringed throughout, tapering from the point of 
origin to the calycle. The liydrotheca is a little swollen at center 
and has a slightly everted and smooth margin. 
Diaphragm. A simple shelf projecting inwards from the cup. 
The basal chamber is not separated from the cavity of the stalk. 
Gonosome. Gonothecae are borne in axils and on the branches, 
on short ringed stalks; it is questionable whether they are ever 
borne on the hydrorhiza. They expand rapidly from base to extrem¬ 
ity, where they end in a flattened top with a very shallow and fiat 
projection containing the aperture. Medusae develop on all sides of 
the blastostyle, in most cases as many as 28 developing at once. 
The older ones are fiat with a four-cornered mouth and about 24 
tentacles. 
Dimensions. Height of colony up to 25 mm. ; length of 
hydrotheca, .3 mm. ; diameter of liydrotheca at margin, .25 mm. ; 
length of tendril like processes, 1.2—5 mm.: length of gonotheca, 
.75-.90 mm.; greatest diameter of gonotheca, .15 mm.; number of 
tentacles on hydranth about 24. 
The tendril like processes which form such a striking feature of 
this species are decidedly characteristic and cannot be mistaken. 
Other characteristic features are the long regular branches, each of 
which bears two or three gonothecae always in axils of branches or 
liydrothecae-stems. 
Habitat. On water grasses. Abundant in Scow Bay, Port 
To wn sen d Harbor. 
16. Obelia fragilis sp. nov. PI. 3, figs. 15, 15a, 15b. PI. 6 , 
fig. 15c. 
Troph osome. Hydrocaulus clinging and never erect. Stems 
polysiphonic, long, flexuous, branched at regular intervals, branches 
also comparatively long and flexuous, slightly ringed at the base 
and with four rings above each branch. liydrotheca deep bell- 
