II.— ZOOLOGY. 



Akt. XXI. — Ncir Zealand Sponges : Third Paper. 



By H. B. KiEK, M.A. 



IRead before, the Wellington I'hilosoijhical Society, 8th December, 1895.] 



Plates III. and IV. 



It is proposed to deal in the present paper with the New Zea- 

 land Eeticulate Aseous, so far as they are yet known to the 

 writer. It is not necessary to review here the various schemes 

 that have been proposed for the classification of these sponges. 

 I simply state, therefore, that I follow the plan proposed by 

 Bowerbank, and followed by Polejaeff and others, of regarding 

 the ascons as constituting a single genus, and adopt Dendy's 

 subdivision into simple, reticulate, and radiate, and, with the 

 modifications that I am about to mention, his further sub- 

 division of the Eeticulata. In Dr. Dendy's classification''' the 

 ingrowths of mesoderm, covered or not by collared cells, con- 

 stitute an important feature. In the New Zealand ascons, at 

 all events, this feature is too variable to be a reliable element 

 in classification, and it is probable that the same variableness 

 in this respect exists in the ascons of other countries. The 

 mesodermal ingrowths may not be found at all in one speci- 

 men, and in another, undoubtedly of the same species, they 

 may be found to be very well marked mdeed. I think I am 

 right in saying that Dr. Dendy does not now attach to this 

 feature the weight that he attached to it when the Monograph 

 was begun. 



Abandoning this feature as an element in classification, Dr. 

 Dendy's scheme, as applied to the New Zealand sponges, takes 

 this form : — 



Order Homoccela. 



Genus Leucosolenia. 



Section II. Reticulata. 

 Division I. — Pseudoderms not present. Leucosolenia clatJirus. 

 Division II. — Pseudoderms present. 



* See " Monograph of the Victorian Sponges," Trans. Roy. Soc. of 

 Vict., vol. iii., p. 1. 



