H. B. Kirk. — On New Zealand Sponges. 287 



■closely watched the flight of this wonderful bird know, is ever in 

 motion, sometimes flapping on the surface of the sea as it dips 

 to a wave, or elevated as it turns in the force of the gale, and, 

 though no doubt difficult to observe, it is in constant quiver 

 of slight rotation of the broad plumes, opening and closing like 

 Venetian blinds. We have in the mechanism thus described 

 a sufficient source to sustain the prolonged, and to the casual 

 observer apparently effortless, flight of the albatros. The 

 locking of the elbow-joint in the albatros is exactly analogous 

 to the locking of the knee-joint of the human skeleton by 

 which man maintains without fatigue that erect attitude 

 which proclaims his supremacy. 



It is very much to the point that the only other bird which 

 posseses a patelloid bone controlling the elbow-joint as the 

 patella does the knee-joint is the penguin, and in this case 

 the wing-bones have also to be kept rigid during the penguin's 

 flight under the water. 



Art. XXXIV. — Further Contribution to a Knowledge of the 



New Zealand Sponges. 



By H. B. Kirk, M.A. 



r Read before the Wellington Philosophical Society, 28th November, 



1894.] 



Plates XXIV.-XXVI. 



In my former paper on New Zealand sponges I expressed an 

 intention of describing the New Zealand sponges in something 

 like their natural order. I think it best, however, to describe 

 at once the two very interesting sponges that form the subject 

 of this paper. I also abandon the intention of copying, except 

 in rare instances, the descriptions of New Zealand sponges 

 already published. 



Sycon dendyi, n. sp. Plate XXIV. 



The genus Sycon is thus defined in Dr. Dendy's " Synopsis 

 of the Australian Calcarea Heterocoela " : Sycettidae with 

 " radial chambers not inter-communicating; articulate tubar 

 skeleton ; the distal ends of the chambers provided each 

 with a tuft of oxeote spicules." 



The definition above {ziveu, taken with that of the family 

 Sycettidae, did not contemplate the inclusion of such a sponge 

 as forms the subject of this paper — a sponge that has a well- 

 developed cortical skeleton of large oxea, through which the 



