876 T, i:\VIS HENKY (;(»UGH. 



nuclei are oblong, witli two or tliree cliromatin bodies, and 

 resemble to some extent tliose of the uterine nutritive cells. 

 The presence of the developing paruterine organ causes tlie 

 wall of the uterus to bulge outwards at a very early stage. 

 The portion thus pressed outwards is at first hemispherical, 

 opening directly into the main body of the uterus, this portion 

 might be termed the paruterine pouch (fi<>-. 53). The next 

 changes take place very quickly, and we find the mouth of the 

 pouch contracting, the contraction being effected by muscles 

 running around this portion of the uterus. As the contraction 

 ])i-oceeds the pouch becomes more nearly globular, until it is 

 finally almost spherical, remaining connected with the 

 remainder of the uterus by a very narrow passage. These 

 changes of their receptacle are not without their effect on the 

 lamella^, whose shape has to accommodate itself to the changes 

 in form of the pouch ; as they remain arranged parallel to the 

 Avails of the pouch they, too, become spherical ; but the 

 lamellas are also growing quickly, and some of them force 

 their way into the uterus as concentric hemispheres, whilst 

 others form concentric hemispheres within the pouch. The 

 lamellse projecting into the uterus appear to grow very 

 quickly, pressing the uterus and its eggs further and further 

 away from the pouch ; the uterus, which was at first merely 

 a transverse tube, becomes globular through the invasion of 

 the lamellae, which have become almost spherical. Finally, as 

 the lamelltfi are still grooving and as they have no more room 

 to spread outwards, the only outlet remaining for them is by 

 doubling back. Depressions appear on the surface of the 

 lamella), deepen, pass through the neck into the pouch, 

 carrying the eggs, which are already enclosed in their two 

 envelopes and contain embryos, with them into the paruterine 

 pouch. Finally, the lamellas appear to complete the process 

 of retroversion and return entii^ely through the neck of the 

 pouch : none are left outside the pouch at all events. The 

 growing back always takes place at several points at the same 

 time, thus giving rise to more than one pocket ; six or seven 

 ai-e usually formed (figs. 53-56, ^^p.). 



