102 Mr. H. J. Carter on the Origin 



to each of which separately it is necessary to direct attention, 

 viz. : — 



1st. A spherical, transparent, empty one, about 10-6000ths 

 of an inch in diameter, bearing a granular lenticular nucleus in 

 the periphery about 1 -6000th of an inch in diameter, from 

 which occasionally might be seen very delicate branched lines 

 of sarcode streaming over the inner aspect (Plate X. fig. 1). 



This kind of cell was very numerous, and, shortly after the 

 fragment of Esperia had been torn to pieces for microscopic 

 examination, was observed to congregate more or less here 

 and there together, and become united with the neighbouring 

 granules and polymorphic bodies of the sponge into separate 

 agglomerations, well represented by Schmidt in his figure of 

 the like from Esperia Contarenii (Adriatic Sponges, Histologic, 

 1864, 1st Suppl. Taf. i. fig. 5). It was observed too that 

 there were many lenticular bodies about the field, composed 

 entirely of granules without visible nucleus (fig. 2), almost 

 identical with the nucleus of the large empty transparent cell ; 

 while the addition of alcohol caused the latter so to collapse 

 round its nucleus, that this also then presented the same 

 appearance : hence it became evident that the large, empty, 

 spherical cell was derived from a plastic layer united to the 

 circumference of the lenticular nucleus, but otherwise capable 

 of being separated from its inner side by aqueous distention 

 into the globular form mentioned. 



2nd. A cell bearing the inequianchovate of Esperia in 

 different stages of development, from 2 to 5 6000ths of an inch 

 long. This, from the generally elliptical form of the spicule, 

 assumed by contraction a similar shape, and thus, through its 

 living plasticity, often became so closely wrapt round its 

 contents as to leave hardly any thing visible beyond the 

 nucleus and granular plasma of which the cell was composed 

 (figs. 13-16). 



Here it is desirable to state that, in its early development, 

 viz. when the cell is perfectly elliptical and about 2 6000ths 

 of an inch long, the embryo spicule appears in the form of an 

 e^m'anchorate (fig. 13), and does not pass into the inequi- 

 anchorate form until it has got beyond this size, when the 

 inequianchorate end appears to proceed and the other to be 

 arrested in its development (fig. 16). This to me is a matter 

 of interest, inasmuch as I have made the presence of minute 

 eg'manchorates, in addition to the others, in some specimens of 

 Esperia a point of distinction ; while it would now appear 

 that they are merely the early stage of the zrceg'manchorate, 

 and therefore so far valueless. Indeed I am quite convinced 

 that great confusion will arise from this point having hitherto 



