CALKINS: SOME HYDROIDS FROM PUGET SOUND. 
357 
Habitat. On piles and stones at Bremerton. Common. 
18. Obelia plicata Hincks. 
This species with its exceedingly delicate calycles was not very 
abundant or in good condition. The polysiphonic stems and the 
method of branching together with the short-ringed pedicels place 
it in this species. 
19. Obelia gelatinosa Pallas. 
A fine specimen of this widely distributed species was dredged 
at Discovery Bay, but it was not in fruit. 
Diaphragm a simple partition below the hydranth turning down 
to form a tube about the coenosarc. The basal chamber is a part 
of the stem. 
20. Obelia griffini sp. nov. PI. 4, figs. 18, 18a, 18b, 18c. 
PI. 6, fig. 18d. 
Tropliosome. The stems are much branched growing on creeping- 
stolons. Branches are regularly alternate and about .5 mm. apart, 
giving a much-branched appearance to the colony. The primary 
stems are ringed at the base (6 rings) and above the joints up to 
middle of the internode. The hydrothecae are borne on stems 
.1 mm. long, ringed, as a rule, throughout the entire length (about 
9 rings). The hydrothecae are alternately arranged, with plain rim, 
deep and gracefully curved. Tentacles on hydranth about 24. 
Diaphragm a simple partition with down-turned edges. The 
coenosarc broadens out below to fill partly the basal chamber which 
is a part of the stalk. 
Gonosome. The gonotliecae are elongate, borne on short ringed 
stalks, rather attenuate and nearly uniform in diameter. From six to 
eight medusae develop on the blastostyle at one time. The older 
medusae are discoid, with about 24 tentacles. 
Dimensions. Height of colony, 25-50 mm.; distance between 
hydrothecae, .08 mm.; length of hydrotheca, .25-.S5 mm.; length 
of gonotheca, .8-1. mm.; diameter at widest part, .25-3 mm. 
Calicella Hincks (in part). 
Schneider does not consider the operculum of sufficient impor¬ 
tance to distinguish genera and unites with his family Campanu- 
lariidae the four families of Hincks as follows : (1) Campanulariidae, 
(2) Campanulinidae, (3) Leptoscyphidae, (4) Lafoeidae. He 
