24 Dr. M. Cougtitrey on New-Zealand Hydroida. 



notes for further observations, though the New-Zealand fauna 

 presents many peculiarities in this respect. Indeed to-day 

 (September 24, 1875) I discovered a pretty freshwater Hydra, 

 in some pond- water, attached to one of the leaves of the plant 

 Natella ucra. This Hydra in general form is like H. viridis, 

 Linn., in colour pale brown, and has seven tentacula, which 

 are peculiar in this respect, that they are distinctly annulated 

 and each ring is fringed. 



Suborder Thecaphoea, Hincks. 



Family Campanulariidge. 



Genus Obelia. 



Ohelia genicxdata, Linnasus ; Hincks, loc. cit. p. 149. ( Vide 

 Coughtrey, Trans. N.Z. Inst. vol. vii. p. 290, pi. xx. fig. 42.) 



This widely distributed species is present in New Zealand. 

 It differs from the British specimens in the following parti- 

 culars : it is more robust in habit, its hydrothec^ are larger, 

 and its gonothecee present some peculiarities. In many spe- 

 cimens these are decidedly urceolate, as figured by me ; but 

 occasionally on the same colony there may be observed one 

 or two reproductive capsules that have a similar form to the 

 nutritive calycles, only that they are quite as large as the 

 other gonothecse. 



The habitat of this species will enable me to present one 

 or two points of interest in connexion with those masses of 

 floating seaweed in w^iich Prof. Agardh, of Lund, has ex- 

 hibited an interest. There grows most luxuriantly in the 

 southern harbours of the New-Zealand and Australian coasts, 

 within and a little below ordinary tidal limits, a fucus which 

 seems to me to be ^^ Macrocystis pyrifera^^ of Decaisue. 

 Wherever I have found fronds of this seaweed in the neigh- 

 bourhood of land, I have got 0, geniculata upon it. And 

 I have found it in the following localities : — east and south 

 coasts of Middle Island, New Zealand ; King George's Sound 

 and Glenelg, Australia 5 also in Port-Philip Harbour and Bass 

 Strait (loose and floating). 



When 0. geniculata attaches itself to a virgin frond, it spreads 

 in a peculiar manner : there is one parent or primary shoot, 

 which runs generally obliquely across the frond ; and this gives 

 ofl" from one side several shoots, which run in the long direc- 

 tion of the frond quite parallel to one another, and but rarely 

 communicating with one another by lateral shoots. From the 

 longitudinal stoloniferous shoots there are sent up at regular 



