HYDROID ZOOPHYTES. 21 



Gonosome. — The gonothecse (fig. 21, gth.) are immature and about O'S x 0*4 mm. 

 in size. They are all female. They arise from the hydrocauli immediately below 

 the hydrothecse and are sessile. They are smooth, pear-shaped, and have a straight 

 margin. No gonophores can be seen, the ova being embedded in the blastostyles. 



This species is also quite distinct. 



DlCTYOCLADIUM FUSCUM. 



(Plate III., fig. 22.) 



Locality. — Cape Wadworth, Coulman Island, January 15th, 1902 ; 8-15 fms. 

 Bottom stones. 



Hydrosome.—T'he single specimen of this species forms a thick, shrubby, fan- 

 shaped colony, 90 mm. in height, 80 mm. in width in the widest part, and about 

 25 mm. thick, i.e., in a direction at right angles to the line of greatest width and the 

 line of height. The principal branches arise irregularly from the main stem, but 

 the smaller and ultimate branches are flabellate in their mode of ramification. 

 The colony as a whole is rendered more compact than it otherwise would be by 

 the ends of several branches developing stolons (fig. 22, 6'^.) which attach themselves 

 to other branches around the bases of their whorls of hydrothecfe. At the .base 

 the colony is polysiphonic, but distally the branches are all monosiphonic. The 

 base and hydrorhiza are missing. 



The hydrothecse (fig. 22, hth.) are arranged in six rows and almost always in 

 regular verticels of three, but sometimes the three hydrothecse of a verticel are not 

 quite on the same plane. They are about 0"8 mm. in length and 0*3 mm. in 

 diameter, and adnate for about one-half to two-thirds of their length. They are 

 very slightly constricted towards the opening, the margin is quite plain and often 

 suddenly everted quite close to the edge. Eeduplication of the hydrothecse frequently 

 occurs, but the secondary thecse project very little beyond the margin of the 

 primary ones. 



The soft parts are quite macerated. 



The general colour of the colony is pale brown. 



Gonosome. — Unknown . 



The species differs from Professor Nutting's diagnosis of the genus (19: p. 105) 

 in the absence of any operculum. In the type species of the genus {D. dichotomum, 

 AUman ; 3 : pp. 7Q-77 ; PI. 36, figs. 2, 2a) the anastomosing stolons coalesce with 

 the mouths of the hydrothecse, the cavities of the hydrothecse and stolons being- 

 continuous ; but in our species these stolons always grasp the hydrocauli at the base 

 of the verticels of hydrothecse. The species differs from both D. dichotomum of 

 AUman and D. flahellum of Nutting in the shape of the hydrothecse and in other 

 characters. Unfortunately Allman does not mention whether an operculum is 

 present in his species or not. 



