HYDEOID ZOOPHYTES. 15 



Hydrosome. — ^The hydrocaulus is unbranched and about 2 mm. in diameter 

 at the distal end. It rises to a height of 70 mm. At its base, where it is 

 extraordinarily slender, there are three or four hydrorhizal branches. It is invested 

 by a continuous smooth tube of perisarc. At the base of the flask-shaped hydranth 

 the hydrocaulus is slightly constricted. 



Just above this constriction the hydranth expands to form the support of the 

 proximal circlet of tentacles. The tentacles of this proximal circlet are 25 in 

 number and about 12 mm. in length. Just above this circlet of tentacles arise the 

 eight long slender blastostyles. 



From the base of the blastostyles the hydranth narrows rapidly to form the 

 conical hypostome surrounded by a dense tuft of distal tentacles, each about 2 mm. 

 in length. 



Gonosome. — The eight blastostyles are in the contracted condition of spirit 

 specimens about 14 mm. in length and bear a great number of flattened gonophores. 

 The gonophores are all female, and about 2 mm. x 2 • 5 mm. in size. They have 

 no radial or ring canals, but, like Tubular ia hodgsoni, they have four rudimentary 

 tentacles. 



Actinulse with proximal tentacles. 



This form appears to be most closely allied to T. spectabilis (Agassiz) from the 

 coast of Massachusetts, described by Allman (2 : pp. 414-5, see also pp. 416-7), in 

 size and general form ; but as the description is not very full, it is not possible to 

 determine the identity of the two species with certainty. 



It differs, however, from the description of T. spectabilis in having the 

 blastostyles disposed in a single row, and not in two or three rows one over the 

 other. 



Moreover, the hydrorhiza of our specimens shows no sign of being " very 

 much contorted, irregularly branched, and densely intertwined." 



CORYNIDAE. 



Species A. 



Locality.— ^.q., McMurdo Bay, February 20th, 1902; -20 fms. 



A single hydranth was found at the bottom of the bottle containing various 

 hydroids from this locality, which appears to belong to some genus of the family 

 Corynidae. Without further evidence than we possess at present we cannot even 

 venture to suggest the name of the genus to which it belongs. 



The hydranth is about • 7 mm. in height, and almost spherical in shape. It 

 has a conical hypostome and six scattered capitate tentacles. The presence of a 

 short stolon or stem at the base of the hydranth suggests that the species is 

 colonial in habit. 



No gonophores are present. 



