152 



I. IKE DA. 



Explanation of Pl. V. 



All figures relate to Phoronis ijimai Ik. 



Fig. 1. — Cross section of a contractile capillary, externally covered over 

 by a layer of large nutriment cells (" Fettgewebe ") derived from 

 the peritoneal cells, a, b, large and small nutriment spheres. In 

 the center are seen two blood corpuscles {b.c.), lying in the 

 capillary lumen which is lined by the flat endothelium. (Zeiss, 

 oc. 2 and imm. syst. T V). 



Fig. 2. — The efferent blood-vessel (ef.) in cross section and a piece of an 

 ovarian capillary in longitudinal section, c.l., capillary lumen, 

 lined by endothelium, /.p., flat and small peritoneal cells 

 remaining at base of the nutriment cells. fol., egg-follicles. 

 og., proliferating oogonia. (Zeiss, oc. 2 and imm. syst. T V). 



Fig. 3.- — Cross-section of an ovarian capillary. Below and to the left, a 

 small oocyte over which the nutriment layer is degenerating. 

 Over the larger egg-follicles that layer has entirely disappeared. 

 I.e., capillar}' lumen. (Zeiss, oc. 2 and imm. syst. T V). 



Fig. 4. — Same. Centrally, three blood-corpuscles in the capillary lumen. 

 A — E, oocytes in differet stages of growth, n and ri, two kinds 

 of nucleolus, x, comma-like body of unknown character, attached 

 to the inner surface of nuclear membrane. (Zeiss, oc. 4 and imm. 

 syst. T V). 



Fig. 5. — Cross section of a functional testicular capillary. Centrally, a 

 blood-corpuscle in the capillary lumen. Radially arranged sper- 

 matogonia strings, each with an axis of a connective-tissue 

 bundle, a — b, stages in the spermatogenesis corresponding to 

 those denoted by the same letters in fig. (5. (Zeiss, oc. 6 and 

 obj. 1.5 mm. apochrom. imm.). 



Fig. G. — Stages in the spermatogenesis, a — b, different phases of nuclear 

 change in the spermatocyte, c, one of the two daughter cells 

 formed by the first division of a spermatocyte ; the nuclear figure 



