49 



packed with alxmt a dozen grains (X-) of one colour and one odd one (b) (nucleus, 

 nuclcoUis ?), which stains a different shade. The outer sheath of rolls each has a small 

 nucleus ( ) and minute nucleolus (/). This sheath appears in some cases to surround 

 the inner cell entirely, and in other cases only to surround the outer part, and not to 

 exist between the inner cell (</) and the other half (<i) of the ovum. 



It is possible that the smaller half of the ovum may be a feeding cell, supplying 

 nourishment to the larger half. The hyaline sphere of grains may I PC food material. 



In the ovum of Meynpoytm mripihis, the smaller half has a somewhat different 

 appearance, which suggests that it is made up of several concentric sheaths of cells 

 round a central one. These ova, however, are not well enough fixed to repay detailed 

 examination. 



REFERENCE LIST OF MEMOIRS CITED. 



1. Mix. HIV. E. A. A Treatise on Zoology. Edited by E. Rny Lankeatcr. Part II. The Porifcra and 



(VlmUr.i. Chapter III. Sponges, by E. A. Mint-bin, M.A. 1'JIK). 



2. DKHDY, A.. Studies on the Comparative Anatomy of Sjionyts. V. Obwrvatioiw on the Structure and 



Classification of the Calcarea Heterococla. Q. J. M. 8., vol. 85 (1893), pp. 169-257, PI. X.-XIV. 

 New Sum* 



3. HABCKBU Die KaUuchtcamme. Berlin. 1872. 



4. PmMAKrr.Challfnffer Rep. VIII. 1883. 



5. BKMTruss. Zool. Jahrbuch, Syst. XI. (1898.) 



6. LKNDKJJKKLU, R. VON. Die Spongim tier Adria. I. Die Kalkachwamme. Zeit. f. wisg. ZooL LI 1 1. 



(1891.) pp. 1-212. 



7. DuiDT, A. Synoptit of Australian Calearea Heterototla .- irith a proponetl clattification of the group and 



dfMriptiont of tome nfir genera and sj)ff iff. Proc. Roy. Soc. of Victoria. Vol. V. (1892), pp. 69-116. 



8. SIiHCHlH, E. A. The Char otter and Synonomy of Uu British ^jierifs of Sponget oftheyentu Leucotolenia 



Proc. ZooL Soc. Lond. 1904, Vol. ii., p. 349. 



2 o 2 



