CALCAREA. 49 



packed with about a dozen grains (k) of one colour and one fxld one (6) (nudeas, 

 nucleol-us ?), which stains a different shade. The outer sheath of cells each has a small 

 nucleus (') and minute nucleolas (/). This nheath apj^ears in some cases to surround 

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

 exist between the inner <:ell (//) and the other half (a) of the ovum- 

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

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



In the ovum of Megapoijon raripilus, the smaller half has a somewhat difl'erent 

 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 dctailcl 

 examination. 



REFERENCE LIST OF MEMOIRS CITED. 



1. ilixcHix, E. A. — A Treatise on Zooloyy. Edited br E. Ray Lankester. Part IL The Pori/era and 



Coelentfcra. Chapter III. Sporj«res, by E. A. 3Iinchin, 3I.A. l^oO. 



2. Desdy, a.— Studies on tf^e Comparative Anatomy of Sporujea. V. Obgervations on the fkrvKime and 



Classification of the Calcarea Heterocoe'.a. Q. J. M. S., vol 35 (1893), pp. 159-257, PL X.-XIV. 

 Xew Series. 



3. Haeckel. — Im Kalk^diwamme. Berlin. 1872. 



4. PoLEJAEFF.— 6%a77«w^er Bep. VIIL 1883. 



5. IlEEiTFUSS.— Zool. Jahrbncb, Sy.st. XI. (1898.) 



6. LESDEiTELD, R. VOX. — Die Spongien der Adria. I. Die Kalkscbwammfe. Zeit. f. wias. ZooL LIIL 



a891.) pp. 1-212. 



7. Dexdy, a. — Synopm of Australian Calcarea Beifrocoela .- with a jirvponed daatificatinn of Om group awl 



d^sitrijjftiowi of iOffie ru:v: ymera and fsjteden. Proc. Roy. .Soc of XuMfnu. Tol. V. (1><'j2), pp. </.i-lV,. 

 8- MisCHis, E. A. — Ttie CfiaraderK and Symmomy of tfu Britinh Specien of Sponyen ofttu^ymwi LmcomUmvi 

 Proc. ZooL Soa Lond. 1904, ToL iL, p. 349. 



2 O 2 



