248 MR J. T. CUNNINGHAM ON THE REPRODUCTIVE ORGANS 



of Bdellostoma agrees with that of Myxine in falling within the coldest season 

 of the year. Myjcine glutinosa, in the North Sea, deposits its eggs in December, 

 January, and February, and the two latter months agree in meteorological 

 conditions with the months of August and September in the latitude of Cape 

 Town. 



The egg of Bdellostoma at the stage under consideration has a thicker and 

 stronger vitelline membrane than the egg of Myxine. I found it impossible to 

 strip off from preserved specimens of the latter the connective tissue and 

 follicular epithelium without rupturing the vitelline membrane. In the eggs of 

 Bdellostoma this could be accomplished with ease. The membrane, when 

 exposed, was seen to be yellowish-brown in colour, and translucent. Round 

 the micropylar end of the capsule formed by the membrane is seen a distinct 

 thin line, forming a complete ring, and it is evident that the micropylar 

 end forms an operculum which separates from the rest of the capsule 

 along this line. Steenstrup has figured a detached operculum in the figure 

 he gives of the ova of Myxine, but in the latter form I have not yet detected 

 indications of the structure. There can be no doubt, from the appear- 

 ance seen in the Bdellostoma ovum, that the escape of the embryo in the 

 Myxinoids is effected by the removal of an operculum specially adapted for 

 that purpose. 



The Teleostean ova I have next to describe resemble in the character of the 

 vitelline membrane the ova of the Myxinoids. Each ovum is spherical in 

 shape, 1*5 to 1*6 mm. in diameter, and about one pole of the sphere is pro- 

 vided with a number of long thin flexible filaments springing from the vitelline 

 membrane. Each filament commences at the attached base with a conical 

 papilla, which is thicker than the filament itself. By the interlacing of the 

 filaments a large number, many thousands, of eggs are connected together 

 to form a cylindrical mass about an inch wide, and a foot or more in length. 

 The felted filaments form a rope-like core to the cylinder, the eggs forming 

 an external layer. Besides the long filaments, each egg shows a similar 

 number of short filaments springing from the opposite pole. These are very 

 slender, and only from 2 mm. to 15 cm. in length. In other respects they 

 resemble the long filaments, of which they are evidently rudimentary repre- 

 sentatives. They seem to have no function, being too small to afford any 

 assistance in the process of attachment. It is probable, though I have not 

 been yet able to demonstrate the fact, that the micropyle is situated in the 

 centre of the region whence the long filaments arise. If this were so, the rela- 

 tions of the filaments and vitelline membrane in this Teleostean egg would be 

 exactly similar to those which obtain in the ovum of the Myxinoids. And 

 whatever be the position of the micropyle, it is interesting to note that the 

 occurrence of a group of filamentous processes of the vitelline membrane at each 



