6\ F. Clark on Neio and Rare Species of Hydro ids. 59 



or four auimliitions just al)ove the origin of each branch; mode of 

 branching irregular, two branches often starting from a node, some- 

 times an alternate arrangement of branches on opposite sides of the 

 stem, one branch at each node. A few o\ the lowest branches some- 

 times attain a considerable length and resemble the main stem, the 

 upper ones are short, sparingly branched and with the pinnae diverg- 

 ing at a slight angle ; the branchlets and ends of the branches are 

 simple, slender, translucent, and very graceful. Ilydrothec* very 

 deeply canipanulate, tapering slightly toward the base, and with nine 

 to twelve longitudinal lines extending from the distal extremity 

 nearly to the base; the rim is ornamented with from eighteen to 

 twenty-four very aciite teeth, arranged in pairs, the spaces in which 

 the longitudinal markings terminate being a trifle wider and deeper 

 than the alternate spaces ; the pedicels supporting the hydrothecae 

 are usually short and stout, consisting of three to six strong rings, but 

 some of the hydrothecae near the base of the stem have the pedicel 

 slightly tapering, and composed of from ten to twelve annulations. 

 GonotheciB unknown. 



The largest specimen has a height of about 6 inches (150'"'"). 



We have had this species from but one locality, Greenport, Long 

 Island, where it was collected August 5th, 1874, in considerable 

 abundance, on the piles of the wharves at low^ water, — U. S. Fish 

 Commission. 



0. hideiitata resembles 0. gelatinosa in the delicacy and grace of 

 its habit, in the flexibility of the compound stem and branches, and 

 in the pellucid whiteness of the upper portion of its branches and 

 branchlets. 



Campanularia pygmaea, sp- nov. 



Plate IX, fig. 9. 



Stem often creeping, with short, stout, coarsely annulated, upright 

 pedicels, sometimes with one or two short, annulated branches, each 

 bearing a single calycle. Ilydrothecpe large, deep campanulate, 

 tapering slightly toward the base, and with longitudinal lines at 

 regular intervals, extending down al)out one-fourth the length of the 

 calycle ; the rim is ornamented with from ten to fourteen square-cut 

 denticles, which are more or less hollowed out above, and separated 

 by rather shallow evenly i-ounded notches, of about the same breadth. 

 Gonotheca? unknown. Height about 1""". 



Found gi-owing on a specimen of Sertularia latlusoda, from Casco 

 Bay, Maine, — U. S. Fish Commission. 



