180 



lo a relatively very large size, — about H nun dianieler of disk and ca. 20 nini 

 length of the arms, which may have up to about 10 joints — before they 

 are liberated, the ovaries must be distended to quite an enormous extent, 

 and on account of the growing long arms of llie young, which need con- 

 siderable room even if bent u|), must occupy any space left between I lie 

 stomach and the body wall. These are the sacs observed by Studer and 

 Lyman and taken by these authors to be the bursa* themselves (Studer) 

 or pockets from the bursie (Lyman); as a matter of fact they have nothing 

 at all to do with the bursse; they are nothing but the distended ovaries. 

 The bursa' themselves are of the typical shape, not at all especially widened, 

 and they never contain young. 



The question, how the young are liberated cannot be directly answered, 

 (considering the great number of young found in adult specimens, it should 

 be expected that specimens having emptied out their young would show 

 distinct traces of the way the young have been passing. Only three ways 

 are possible; either they must pass directly through the body wall, rup- 

 turing the sac within which they have developed, or they must pass through 

 the bursal wall, likewise after ru{)turing the ovarial sac, or finally there 

 may be a natural opening from this sac through the bursal wall, through 

 which they may pass. As there is never seen any traces of scars on the 

 disk, and not on the bursal wall either, in specimens which have emptied 

 the young, and the empty ovarial sacs are likewise unruptured, there can 

 hardly be any doubt that there must be an opening from the ovarial sac 

 through the bursal wall. As no such ojiening can be seen, it must be capable 

 of widening to a very large extent and then completely closing again. — 

 Through this opening also the spermatozoa must enter for ferlihzing the 

 egg. It is a remarkable fact, however, that nobody appears to have 

 observed specimens with the young in the act of being liberated, such as 

 is seen so very often in other viviparous Ophiurids. 



After the liberation of the young the ovarial sacs shrink very consider- 

 ably, the wall contracting and becoming much thicker; it remains attached 

 to the body wall and the stomach and bursal walls through numerous 

 trabecules of connective tissue, as observed by Lyman. But they do not 

 disappear or reassume the original shape of an ovary. 



The propagation begins at a very early stage; already in a specimen 

 of 13 mm diameter of disk a large young was found, so that the sexual 

 activity must have started here at a size of only ca. 12 mm diameter of 

 disk. In another specimen of 16 mm only larvje, not yet metamorphosed, 

 were found. But this specimen was unusually late in beginning its sexual 

 activity, which may be stated to begin, as a rule, at a size of ca. 13 — 11 mm 

 diameter of disk, that is to say very soon after they are born. In sucii 



