EMliKYOLOGY OF CLEPSINE. 235 



effect of carmine is alike in both cases very weak. This bod}^, 

 which appears as a pellucid spot on fresh eggs, and which, 

 according to the terminology of van Beneden and Fol, may be 

 designated ?i& female pronucleus , is the remnant of the Archiam- 

 phiaster. It is without a membrane, perfectly homogeneous, and 

 forms the centre of a radial system. Not far from the opposite 

 pole is another similar body — also the centre of a radial system. 

 The latter body is the male pro7mcleus^ (Spermakern, Hertwifj). 

 There appear to be three polar globules in this case (fig. 65, B), 

 two of which are about the same size (circa .03 mm.), and con- 

 tain nuclear bodies. Opaque granules are quite numerous except 

 in one which is quite transparent. 



Ten minutes later (1 h. 25 min.) I have seen a circular area 

 at the oral pole assume a somewhat darker shade than the rest 

 of the egg (PI. XII., fig. 8). I have recognised this change but 

 once with certainty (by very favourable light), and can give no 

 explanation of its origin or signification. 



Five minutes later (1 h. 30 min.j a transj)arent fiuid substance 

 begins to collect in a shallow groove which encircles the oral 

 pole, thus forming the first polar ring (Pi. XII, fig. 9). This 

 ring, at fi^rst feebly expressed, soon becomes well defined, and is 

 bordered both on the polar and also on the equatorial side vvith 

 yolk which is quite free from yolk spheres, but densely packed 

 with fine granules. The borders appear whitish by reflected light. 



As the ring begins to advance towards the pole, at the same 

 time deepening, the inclosed polar yolk, on which the polar 

 globules rest, assumes the form of a calotte (fig. 10). About 

 this time (1 h. 40 min.) a similar ring appears around the aboral 

 pole, and the equatorial edge of the first ring [p.r.) becomes 

 denticulate, the substance of the ring stretching out towards the 

 equator of the &^^ in the form of rays. J ust before these ring- 

 rays have reached their maximum in extent and clearness on the 

 oral pole, they begin to form in the same manner on the aboral 

 pole (fig. 11). The first ring continues to advance towards the 

 pole, reducing the base of the calotte to a slender c ilumn {b, cal.). 



The second ring {p.r'-) advances towards the abjral pole, but 

 not striking deej) enough to form a calotte, drives the inclosed 

 yolk in towards the centre of the egg, and collects in the form 

 of a disc (fig. 11). 



The calotte (cal.) is often reduced to a much smaller extent 

 than is represented in figs. 12, 13, and 14; but it does not 

 wholly disappear. As the time approaches for the beginning of 



^ June TSlli, 1878. I liave found the male pronucleus before the appear- 

 ance of tlie first [jolar globule. Just after deposit the arcliiamphiaster is 

 found at one pole of the egg and the male pronucleus, whicli at, this time 

 resembled in size and general appearance one of the amphiastral poles, near 

 liie opposite pole. 



