756 SOME NEW AND RARE HYDROIDA IN THE AUSTRALIAN MUSEUM, 



CAMPANULARIA (?) SPINULOSA, n.sp. 

 (Plate XII., tigs. 5-7). 



Hydrorhiza slender, climbing ; hydrocaulus about -J inch high, 

 slender, unbranched or with numerous sub-erect branches ; stem 

 and branches nearly straight, with a few rings or spiral turns 

 (mostly 4-6) just above the origin of each peduncle, 6-12 rings 

 usually at the base of each stem or branch ; peducles ringed, those 

 on the upper parts of the hydrophyton consisting of about 5-6 

 rings, those on the lower portions often with 8-10. Hydrothecse 

 alternate, sub-cylindrical in their upper half, tapering below, 

 slightly constricted at the " floor," which is a little above the base, 

 and somewhat oblique ; margin armed with a number of minute 

 slender compressed spines (usually 20-24) arranged in pairs, the 

 margin very slightly sinuated between the two spines of a pair, 

 more deeply sinuated (almost semi-circularly) between the pairs ; 

 hydrotheca marked with faint longitudinal lines, one between 

 every two pairs of spines. 



Gonosome unknown. 



Hob. Port Jackson, on a Tubularia. 



In the form of the hydrothecae, and the arrangement of their 

 marginal teeth, this species is similar to a hydroid described by 

 Clarke under the name of Obelia bidentata* but that species is 

 polysiphonic and grows to the height of six inches, while the 

 specimens of C. spinulosa, which I have examined, are of delicate 

 growth and not more than half an inch in height. It is possible, 

 though perhaps not probable, that the present species is a young 

 form of 0. (?) bidentata ; at present it may be provisionally 

 regarded as distinct. Most of the shoots exhibit the rudiment of 

 a polysiphonic structure, consisting of a delicate stolon which 

 originates from an aperture formed at the outer side of the base of 

 the most proximal peduncle, and grows downward along the 



* Descriptions of new and rare species of hydroids from the New England 

 coast. (Transactions of the Connecticut Academy of Arts and Sciences, 

 Vol. III., Part I.) 



