120 BULLETIN OF THE 



any pores for the egi'ess of eggs, such as exist in the bursa of Ophiurans. 

 It is therefoi'e probable that the membrane ruptures at the breeding 

 season, and the eggs are poured into the radiating compartments of the 

 body-cavity. Here the sea-water might bring in spermatozoa for im- 

 pregnation, after which the eggs of any compartment could be dis- 

 charged thi'ougli any one of the ten genital openings. 



The chief difference between these organs in Gorgonocephalus and 

 among Ophiurans is the greater specialization in the latter, where the 

 lining membrane of the disk-wall becomes free, and eulai'ges opposite 

 each genital opening into a closed pouch (bursa), which is extended in 

 the form of finger-like tubes (ovarial tubes). In other words, the lining 

 membrane, instead of being pierced by the genital opening, is continu- 

 ous and simply becomes free and voluminous. In Gorgonocephalus, on 

 the conti'ary, the genital opening pierces not only the disk-wall, but its 

 lining membrane, and enters the body-cavity, while nearly the whole of 

 the lining membrane takes on the egg-bearing function, and by the 

 growth of the eggs is gradually stretched and thrown into folded 

 lobes. 



A section of a Euryale (Fig. 5) will show the different aspect of a 

 non-gi-avid individual, whose stomach pouches are nearly empty, instead 

 of being stuffed with the clotted substance already mentioned. Above 

 is seen the stomach, which, on the right and left, passes into pouches, 

 St'; and similar partitions, forming pouches, may be seen on the farther 

 side of the centre. Above the lateral pouches are the radial shields, I, I, 

 cut through. On the extreme right and left are greatly dilated genital 

 openings, n o, which lead directly into the body-cavity ; and this, passing 

 under and outside the stomach, is connected, about the mouth, by the 

 perihsemal canal, a cross-cut of which appears at 8f. A section of the 

 disk-skin, above the body-cavity, exhibited a uniform, tough, slightly 

 fibrous texture, with a thin lining membrane, not well defined, and of a 

 granular texture imder a high power indicating perhaps egg-cells. Of 

 fully formed eggs, however, there were none, and the lining membrane 

 was not thrown into lobes or convolutions. If, however, the ovaries 

 were distended and the stomach-pouches filled with matter, the general 

 appearance would approach that of Gorgonocephalus, except that the 

 stomach-pouches would be simpler ; and the ovaries would be much 

 more restricted in area, unless indeed the lining membrane of the body- 

 cavity to which the stomach-wall adheres has the power to develop egg- 

 clusters, and thus form lobes, and push the stomach inward towards the 

 mouth. 



