BIHANG TILL K. SV, VET.-AKAD. HANDL. BAND 27. AFD. IV. N:0 6. 25 



pellicles are stretched between the ovum and the follicular 

 capsule, and that they fuse with their bases and upper ends 

 so as to constitute a series of larger and smaller defective 

 hoUows arranged inside the capsule. Evidently the pellicles 

 have originated from the processes mentioned, these having 

 become fused and transformed. The truth is, that the pro- 

 cesses too, have in general their bases more or less fused 

 together, forming here as well a kind of incomplete mem- 

 branes. Probably, the processes and plasmatic pellicles in Meso- 

 thuria intestinalis are analogous to the albuminous zona ra- 

 diata of other Holothurids, which, however, here is never 

 visible. 



In 1898, IwANZOFF^ states that the unripe ovum of Holo- 

 thuria tubulosa sends out processes through the "Gallertschicht" 

 towards the follicular membrane and somewhat earlier, in 

 1896, Andrews^ appears to have observed the same phenome- 

 non during his studies on "Some spinning activities of proto- 

 plasm in Stariish and Sea-Urchin eggs". 



In unripe ova, on the part facing the lumen of the geni- 

 tal tube, a layer of homogeneous plasm covers the egg like a 

 calotte (Pl. I, hg. 9, 10), the space being crossed by a num- 

 ber of very fine irregular granulated filaments. However, 

 there are no radiating pore-canals to be detected, nor is any 

 micropyle formed. I suppose this to be the preparation for 

 the protrusion of the micropyle-cone, At a slightly låter, 

 stage, the egg sends out through this homogeneous plasma- 

 calotte, besides other processes, an eminent conical protrusion 

 towards the follicular membrane (Pl. I, hg. 12). This beco- 

 mes the micropyle which always seems to have its direction 

 towards the lumen of the genital tube. 



In this earlier developmental stage, the nucleus has taken 

 a decidedly excentral position, and the substance of the ovum 

 has separated into two elementary parts, one coarsely meshed 

 main portion, and another finely granulated part limited to 

 the narrow space between the nucleus and that part of the 

 periphery where the cone protrudes and which corresponds to 



' tjber die physiologische Bedeutung des Processes der Eireifung. Bull. 

 Soc. Natural. Moscou (2) XI, pp. 355 367. I have not had the opportunity 

 of seeing the original paper, but only an extract in "Zool. Jahresbericht 

 fur 189S". Berlin 1899. 



^ Journal of Morphology. Vol. XII. Boston 1897. 



