250 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



Fig. 203. Part of macerated tegumental gland from metastoraa. Compare also fig. 214. From female 

 with ripe ovaries. August 9, 1893. Stained in methyl green. Central cell takes on deepest 

 stain, gd.c, gland-cell; B, central reticulated body ; s.c, ganglion cell. 773 times natural 

 size. 



Fig. 204. Cell from macerated tegumental gland of first maxilla.. Stained in methyl green. 773 times 

 natural size. 



Fig. 205. Gland-cell from same preparation as fig. 204. 773 times natural size. 



Fig. 206. Cell from macerated tegumental gland of abdominal appendage of female before egg extru- 

 sion. Ovaries nearly ripe. Attenuated, central end of cell very refractive. Small 

 bodies, apparently accessory nuclei, are present in cell. 773 times natural size. 



Fig. 207. Same preparation as last, rolled under cover-slip and seen from o2rposite side. 773 times 

 natural size. 



Fig. 208. Tegumental gland from metastoma of female -with ripe ovaries. Macerated three days in 

 Bela Haller's fluid and stained in methyl green. The duct (d) of the gland conld be seen 

 to open directly into a small central chamber, as in fig. 212. 513 times natural size. 



Fig. 209. C41and-cell from tegumental gland of abdominal appendage of female, which had recently 

 laid eggs in an aquarium at the United States Fish Commission station, Woods Hole, Mas- 

 sachusetts. Macerated in Bela Haller's fluid. August 14, 1893. 773 times natural size. 



Fig. 210. Tegumental gland from abdominal appendage of female lobster 10i inches long, preparing to 

 molt. Chromic acid preparation, stained in the Ehrlicb-Biondi anilin mixture. Picro- 

 sulphuric acid gives same result. Cells apparently shrunken, transparent, non-granular; 

 nuclei clear. August 17, 1893. 513 times natural size. 



Fig. 211. Tegumental gland from abdominal appendage of female after ovulation. External eggs in 

 yolk segmentation. Central ends of gland-cells are filled with dark zymogen granules. 

 Nucleus of gland-cell stains green, that of central cell always red, in the Ehrlich-Biondi 

 mixture. August, 1893. gcl.e, gland-cell; s.c, ganglion coll. 513 times natural size. 



Fig. 212. Section of tegumental gland from abdominal appendage of female lobster with mature 

 ovaries. Central part of gland has a bluish clouded appearance. Nuclei may be green or 

 red according to the degree with which the stain is extracted. Stained in the Ehrlich- 

 Biondi mixture. August 4, 1893. d, duct of gland; », nerve-supplying gland; B, central 

 reticulated body. 513 times natural size. 



Fig. 213. Gland-cells from same preparation as figs. 204, 205. Central ends of cells attenuated, and 

 strongly refractive. 773 times natural size. 



Fig. 214. Macerated tegumental gland from metastoma of female, showing the central reticulated 

 body, gland-cells, ganglion cell, and duct of gland. From female with ripe ovaries, d, 

 duct of gland ; B, reticulated body. 773 times natural size. 



Plate 50. 



Fig. 215. Egg before yolk has segmented. The whitish spots are due to the presence of cells which 

 are approaching the surface on one side of the egg. The yolk is later massed up about 

 these in hillocks, as in fig. 218. 29 times natural size. 



Fig. 216. Surface view of egg with 16 cells present near the surface, two double rows of eight cells 

 each." The cells have just divided. This drawing was made at 10.30 p. m. ; at 10.55 p. m. 

 20 cells could be discerned near the surface. 29 times natural size. 



Fig. 217. Same egg as fig. 216; drawing made 1| hours later (12 p. m.), showing the cells more diffused 

 over the surface. 29 times natural size. 



Fig. 218. Same egg as in figs. 216 and 217; rolled to show animal pole and yolk hillocks in profile. 

 Drawing made at 10.55 p. m., when 20 yolk elevations had been formed. On the outskirts 

 of these, other cells can be seen lying below the surface and destined soon to become the 

 centers of new hillocks. 29 times natural size. 



Fig. 219. Surface view of egg showing yolk segments in active division; 10.15 p. m., segmentation 

 furrows complete. This side of egg corresponds to the side shown with yolk hillocks in 

 profile, in fig. 218. Nuclei all dividing at 10 p. m. ; at 10.10 p. m., furrows began to appear, 

 separating cells. Same egg as shown in fig. 220. 29 times natural size. 



Fig. 220. Reverse side of egg shown in fig. 219, corresponding to the right side of the egg shown in 

 fig. 218, opposite the yolk hillocks. When drawn at 9.30 p. in., nuclei were invisible; at 

 10 p. m. they were very distinct and in diaster phase; at 10.15 p. m. segmentation furrows 

 completed. 29 times natural size. 



