54 " ENDEAVOUR " SCIENTIFIC KKSULTS. 



Mesial sarcothecaa adnate to the hydrotheca 1 as far as the 

 margin ; free part short, slender, curved forward, terminal and 

 lateral apertures distinct. Lateral sarcotheca? adnate, saccate, 

 with two circular apertures, one directed forward, the other up- 

 ward ; both often more or less confluent with . the wide lateral 

 aperture. Cauline sarcotheca? similar to the laterals, two on the 

 rachis at the base of each hydrocladium, and a third at the back 

 of each axil. 



Gonosome ? 



Colour. Reddish-brown. 



This species closely resembles H. baileyi and H. fnrcata, 

 between which it is to some extent intermediate. It may have 

 to be classed ultimately as a variety of H. farcata, when our 

 knowledge of the two forms is more extended ; at present it may 

 be provisionally regarded as a distinct species. 



A large colony of it was found accompanying Aglaophetna 

 tasmanica, but whether it had commenced as a parasite on that 

 species, after the fashion of so many of its congeners, was 

 impossible to determine, the stems being matted together with 

 other growths. It divides in a purely dichotomous fashion, and 

 in most cases with considerable regularity, each division 

 bifurcating again at the same distance as its fellow from the 

 previous bifurcation. One specimen has divided four times, 

 all at regular distances, so that the final number of divisions is 

 sixteen. 



In the widely divergent branches and hydrocladia, the latter 

 being almost at right angles, it nearly resembles H. fu-rcata, 

 and both species differ from H. baileyi, in which the hydrocladia 

 are more ascending as well as more directed forwards. The 

 hydroihecae of the three species are much alike, but those of 

 H. furcata are broader in front view (in proportion to their 

 length), than in either of the others. The internodes are longer 

 in H. intermedia than in the others, and the hydrothecas on the 

 proximal parts of the hydrocladia, with their internodes, are 

 rather broader in front view than the more distal ones. 



In H. baileyi the base of each mesial sarcotheca springs 

 directly from the back of the next hydrotheca, in the other 

 two species there is a distinct interval between ; in other words 

 the back of the hydrotheca does not quite extend to the end of the 

 mternode. In the " Catalogue of the Aiistraliau Hydroid 

 Zoophytes " it is stated in error, under H. baileyi, that 

 H. fnrcata is similar in this respect ; they are, however, figured 

 correctly. The central lateral teeth of the hydrotheca are some- 



