GENUS HOPLOPHOEA. 553 



not quite agree with liim ; I think, therefore, that a 

 short note, explanatory of what may be seen by or- 

 dinary observation, without special preparation and 

 without cutting sections of these minute bodies, may 

 be useful to the student. Taking II. magna as a type, 

 the egg is formed in the ovary, and uip to the time of 

 leaving that organ is a minute, almost globular body, 

 attaining, perhaps, '10 mm. in diameter, and consisting 

 of a delicate membranous sac filled with very clear, 

 almost fluid, very homogeneous contents, but in which 

 the centrally placed germinal vesicle was detected by 

 Nicolet. The first one or two eggs in each oviduct 

 are much of the same nature, and not greatly larger ; 

 in the second egg, however, it will usually be seen that 

 the contents have become a little more opaque toward 

 the centre, leaving a more hyaline portion exteriorly ; 

 and of course the size is a little increased (see PI. LI, 

 fig. 2 a). The third or fourth egg usually shows a very 

 marked change, it loses the globular shape, and becomes 

 elongated, and attains nearly its full length ; it may 

 now be nearly '2 mm. Segmentation commences, and 

 proceeds very rapidly, extending over the whole egg ; 

 the membrane also becomes somewhat thickened. One 

 of the eggs in this condition is figured at fig. 2 b. A 

 delicate inner membrane has now formed, which 

 becomes slightly invaginated at the oral pole, and a 

 space appears along one side, apparently below what 

 will ultimately become the ventral surface of the 

 embryo (fig. 2 c). The external membrane of the egg 

 now commences to be irregularly wrinkled or corru- 

 gated towards the oral end, the membrane and yolk 

 contents remaining comparatively unaltered at the 

 aboral end. While this is taking place certain delicate 

 brownish formations appear Avithin the membrane, 

 looking like very fine chitinous blades or rods ; of these 

 two paired curved pieces near the oral pole might 

 possibly indicate the formation of the mandibles ; a 

 short blade along each side sloping upward, and another 

 nearly meeting it and sloping downward might indicate 



