1850.] W 



aggregated together. These when examiBed beneath tibe microseope, aa flie first 

 day after I obuined theoi, exhibited a triiite, gnnalar yolk divided into foar 

 globular massses connected together and snrroimded by a transparent albumoi. 

 Each mass contained in its centre a clear cell or reside. On the second day the 

 separation annong the yolk masses was less distinct and upon the third day the 

 whole had onited into one oTal, finely granular body, and the interim resides 

 had disappeared. The fourth and fifth days no perceptible change was obserra- 

 ble. From the sixth to the ei^th day the yolk had become conical in Chid, aad 

 upon the ninth day the base of the cone exhibited a cleft or fissure whidi by lie 

 tenth day Had extended two thirds the length of the mass. Daring the whole of 

 this period the yolk retained its granalar character and was motionless. Upon 

 the eleventh day it resembled a cylinder doubled upon itself, or the outline of the 

 embryo bad been forward, and one extremity of it, corresponding to the head had 

 become translucent from a solution of the granular matter within. The other or 

 tail end was subacute. The twelfth day the translucency had extended itself in 

 the interior part of the embryo, the extremity of which had advanced beyond the 

 others and presented an emargination communicating with an orifice opening into 

 a canal visible in the interior, and Crom the edge of the extremiry was developed 

 a circle of short filaments which projected downwards and oatwaids. From the 

 thirteenth to the fifteenth day the granular matter had entirely undergone solotioa 

 within the anterior half of the embryo, and the latter had becMne somewhat 

 dilated. The interior canal was also more distinct, and the bordering filaments of 

 the extremity were larger. In the coarse of the sixteenth to the eighteenth day the 

 translucent half of the animal was separated &om the other by a constriction, and 

 the canal in the interior presented at its anterior portion a clavate tubular body, 

 the free end of which projected from the oral aperture. The extremity of the 

 hfead was surronnded by a reflected collar from the free border of which projected 

 tiic filamentary appendages. The posterior half of the embryo was still grs^i:;.ir 

 in appearance, but bad become rounded and somewhat dilated at the extremirr. 

 From the nineteenth to the twentieth day the embryo alternately retracted and 

 ]Kt>tnided the tentacolar or filamentary aj^ndages, and the integament of the 

 anterior half of the body appeared to be getting annulated, which was dis: 

 80 by the twenty-first day. The granular matter in the poster: rr -^- 

 body was also undergoing solution from the periphery towards the : . _: 



its posterior part there appeared several large oil globules. On the rwenry- 

 second day the annulations of the anterior half of the body were ve : 

 posterior half was also becoming annulated, and near its extremitv __ _ ,; 



time observed an anal orifice and one to four small ejMdennal spines. On the 

 twentr-fourth day, the tubular clavate organ before mentioned, : 

 anterior pan of the alimentary canal was alternately protruded an*! ; r 

 proboscis. The proboscis when ftiUy protruded brooght into view a: r 

 second circle of tentacular filaments within the first. On the twenrv-sbc: 

 the embryo when pressed from the egg progressed forward br . 



rior half of its body from side to side, acd it alternately prot" 

 the proboscis and the two circles of tentacular filaments. V 

 organs were retracted, the head presented a truncate or depressed surface, and in 

 their protrusion the extremities of the outer cirde of tentacvLe and the end of die 

 proboscis first became visible ; as these advanced the secood circle o taitacolz 

 ^ipeared, and when the proboscis was entirely protxaded, the outer tentKoIs 



