MARINE BIOLOGICAL STATION AT PORT ERIN. 47 



as has been described in male gonophores of T. hodgsorii 

 (Hickson and Gravely : Hydroid Zoophytes of the 

 National Antarctic Expedition ; Brit. Mns. 1907, p. 14, 

 PI. iv., fig. 34). 



In spite, however, of these well-marked diiferences 

 of anatomy occurring in the one or two specimens of each 

 sex thus carefully examined (and so probably also in the 

 others), as well as of the presence of the large tentacle 

 on the female gonophores, it seems to me, in view of 

 Swenander's statements, to be better to regard Bonnevie's 

 T. obliqua, and so also the Port St. Mary specimens, as 

 a variety of T. indivisa at any rate until further informa- 

 tion is obtained as to the weight to be given to these 

 characters. It would be at least inconvenient to be 

 unable to determine the species of one sex without the 

 examination of carefully prepared sections. 



Obelia longissima, which has up to the present 

 apparently only been recorded from the L.M.B.C. area at 

 Little Ornies Head and Blackpool ("Fauna," Vol. I., 

 p. 102), was found in large quantities by Mr. Dunlop on 

 the lower parts of the lines attached to lobster-pots 

 between Port Erin and Eleshwick Bay. Although the 

 colonies resembled 0. longissima as defined by Hincks in 

 the great depth of the hydrothecae and the straightness 

 of the stem, they resembled 0. flahellata in the dentate 

 margins of the hydrothecae and the subverticillate 

 appearance of the colony due to the forking of the 

 branches at their bases. It is interesting in this con- 

 nection to note that colonies of 0. flahellata dredged near 

 the Isle of Man in 1885 (" Fauna," Vol. I., p. 103) were 

 in a very similar way intermediate between the species 

 to which they were referred and 0. dichotoma. 

 Halecium tenellum, which I gather from the "Fauna," 

 l 



