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POPULAR SCIENCE REVIEW. 
permanently attached to the upper glass of the box, so that it 
was vertical in its position, with the foot next to the eye — a 
favourable aspect for observing the development of the case. 
It presently began to dilate its body, and in about five minutes 
from its attachment, I perceived a distinct filmy ring around it, 
perfectly circular, whose diameter was about twice that of its 
body (plate iv. fig. h). The little animal now began to lean over 
to one side, and the ring soon had another segment additional, 
leaning in the same direction (fig. c). The case, for such it 
was, looked like two broad hoops of glass, each swollen in the 
middle and set one on the other, but not quite concentrically, 
at least to the eye of the observer. It was manifest that it was 
produced by an excretion from the body, owing its form and 
size to the animaPs moving round on the foot as on a pivot. 
Three hours after the hatching, the form of the young animal 
was elongated and maggot-like (in another instance the young 
was eight hours in attaining this stage, while others in the same 
period had the arms well formed and furnished) (fig./); the 
case having the appearance just described. No trace of the 
arms had as yet appeared. Night intervened, and the next 
morning, eleven hours after birth, the arms were beautifully 
formed, and of considerable length (fig. g) ; the mouth-funnel 
was well marked, and the general shape had become character- 
istic : the case had increased in dimensions. At eighteen and 
twenty-four hours, I found the arms becoming more and more 
perfect, and at thirty-six hours after birth it was a perfect httle 
Stephanoceros (fig. i), the outline of the body well developed, 
the principal viscera, the collars, the mouth-funnel, the muscular 
crop, the jaws — all distinct ; the ciliary setae were now arranged 
in whorls of pencils, and vibrated on a slight jar ; the “ urinary” 
concretion behind remained, apparently within the intestine, as 
a sort of meconium. Indistinct traces of the opacities of the 
crop began to be discernible. In the animal at this age, the 
arms, which have attained the full proportional length, are 
carried much more divergent than usual, and it occasionally 
expands the coronal circle nearly to the extent figured by 
Ehrenberg in the adult.* 
* I have not in any case seen the first budding of the arms from the rounded 
front. But Mantel! mentions (and refers to his figures, which are, however, 
very indistinct) a cluster of four or five sub-conical papillae, which in a young 
thirty -hours’ old were perceptible “ within the body ,” and which he supposes 
to have been “ the rudimentary rotatory organs,” in other phrase, the arms. 
Then, again, he mentions, eighty hours after birth, the young as bearing 
“five mammillated projections, fringed with cilia on the upper margin, 
evidently the rudiments of the tentacula.” These latter were doubtless what 
he supposes them to have been, but in the former instance I have some 
suspicion that he merely saw the points of the brachial muscular bands (see 
the fig. of young in plate iii.). He figures a yet further development at 
