No. 3-] EGG OF ALLOLOBOPHORA FCETIDA. 523 



serial sections of this &gg\ but the fifteen reproduced are 

 enough to show the peripheral arrangement of the archoplasm 

 at this stage, i.e., mature egg, with the pronuclei at the early- 

 stages of formation {cf. Photos 57, 58, PL XLIII, for same 

 stage of development at a magnification of 660 diameters ; 

 the latter (Photo 58) is a section of the periphery). In Photo 

 59, PI. XLIII (vignetted section), we have a little later stage, 

 when the archoplasm is no longer distributed around the entire 

 periphery of the Q.gg, but is beginning to concentrate at two 

 nearly opposite areas, preparatory to forming the two polar 

 rings. One of these areas is shown in Photo 59, and suc- 

 cessively later stages in Photos 78-80, PI. XLIV. The pro- 

 nuclei gradually increase in size during these stages. The 

 most common form of the completed polar ring is shown in 

 Photos 82-84, PI. XLIV, but a comparison of these with 

 Photos 80, 81, and 85 will show that this form is not con- 

 stant. (The granular structure of the archoplasm is shown 

 in Photo 84, PI. XLIV; see explanation of plate.) The tiny 

 granules demonstrated throughout the cytoplasm in the stained 

 preparation of Photo 83 resemble morphologically the accumu- 

 lated mass of granules forming the polar rings. 



In Molgula, Crampton (6) finds that the yolk-nucleus, which 

 is typical of one stage of the egg's development, becomes the 

 yolk-spheres (deutoplasmic spheres) of a subsequent stage, 

 his results in the main features supporting Van Bambeke's 

 observations in Pholcus. A comparison of Crampton's figures 

 (i_7) with photos of the young oocytes of PI. XLI will show 

 that the yolk-nuclei in Molgula and in Allolobophora are 

 morphologically alike. The identity of the two substances 

 cannot be insisted upon, however, because of the unusual 

 reaction to haematoxylin, Crampton describes as typical for 

 the yolk-matrix in Molgula. He says : " It is important to 

 note that the yolk-matrix fails to staijt zuith h(Bmatoxylin'' 

 (6), p. 32. In Allolobophora the yolk-nucleus stains intensely 

 with h;£matoxylin, and thus is in accord with its reaction in 

 other forms (Van Bambeke (30), pp. 521, 527). The yolk- 

 spheres in Molgula show a striking morphological resemblance 

 to the deutoplasmic (osmophile) granules in Allolobophora, 



