DEVELOPMENT OF A CHIM.EROID. 



at first attached to stones, etc., by a 

 bulbous tip at the end of the string-like 

 process of the egg-case. 



Copulation takes place shortly be- 

 fore the eggs are deposited, for females 

 with eggs in oviducts are usually found 

 with recent marks of the prehensile or- 

 gans of the male. That the male twists 

 about the female, shark-like, is evident 

 from the character and nearly uniform 

 position of scars near the base of the 

 dorsal fin of the female. These mark- 

 ings, corresponding with the denticles of 

 the frontal organ, indicate that the pair 

 are locked together in copulo. Both 

 mixipterygia appear to be inserted. 



There is evidence from experiments 

 with gravid fish kept in aquaria that the 

 elaborate egg-case (Fig. i) takes but 

 a short time to be formed, possibly not 

 longer than three days. The dilated 

 portion of the case is laid down and is 

 almost perfect, including the lateral pro- 

 cesses before the stalk appears ; during 

 this time the lining of the oviduct be- 

 comes curiously developed to produce 

 the highly specialized structures of the 

 case. The exit-slit or "door" is formed 

 by an abrupt folding in the case's wall. 

 In this folding there is a double row 

 of transversely-directed, interlocking 



FIG. I. Egg-case of ChimcEra colliei. 'Ventral' as- 

 pect. < I. The case is of extraordinary length (about 

 seven inches to the base of the terminal filament) 

 compared with the total length of the female (about 

 twenty-three inches). The egg itself when freshly 

 deposited is elongate and depressed (about ly^ in. 

 x %x.)4 inches), after the fashion of elasmobranchs. 

 It is of similar syrupy consistency, flowing away as 

 soon as the vitellina is ruptured. 



ffl 



FIG. i. 



