EXPLANATION OF PLATES 1-9. loi 



Fig. 21. Optical section of a stage somewhat more achanced than in tlic precedinfr 

 llgure. 



22. A stage directly after the closure of the micromere pole. 



23. Optical section of egg of about the same stage as in Fig. 22. 



24. A stage somewhat more advanced tlian in the preceding figure; view on 

 tentacular plane. 



25. The same; view on sagittal plane. 



Figs. 26-2S. A stage more advanced than the preceding figure; Note the stomodaeal 

 imagination much advanced than in the preceding stage; 



26. View on tentacular plane. 



27. Aboral view, showing the IF shaped endodcrmal space. 



28. View on sagittal plane. 



Plate 7. 



All C. bocki; Figs. i-G, sketches in living state, X 170; I'igs. 7-19, X^oo. 

 Pigs. 1-3. Young cydippid larva; 

 Fig. I. View on tentacular plane. 



2. Aboral view. 



3. View on sagittal plane. 



Figs. 4-6. Larva of somewhat more advanced .tifage; 

 Pig. 4. View on tentacular plane. 



5. Aboral view. 



6. View on sagittal plane. 



Figs. 7~ii- Successive horizontal, but a little obli(iue sections of larva in a stage 

 nearly the same as in Figs. 1-3; planes of sections are shown in Fig. 12, (A-A : Fig. 7, B-B : 

 Fig. 8, C-C: Fig. 9, D-D: Fig. 10, E-E : Fig. 11), 



Fig. 13. Section in transverse plane of larva directly after hatching out. 



Figs. 14-19. Successive horizontal sections of larva in the same stage as in Fig. 13; 

 planes of sections are shown in Fig. 20, (D-D: Fig. 14, E-E: Fig. 15, F-F : Fig. 16, G-G : 

 Fig. 17, H-H : Fig. i8. I-I : Fig. 19). 



Fig. 21. Larva hatching out; X^S- 



22. A stage after completion of matamorphosis; the main parts of endoderm are 

 composed of eight radially-situated subequal pouches. 



Plate 8. 



Gasirodes parasiticnm; Figs. 1-3, X50; Figs. 4-6, X90; Figs. 7-10, X 180. 

 Fig. I. One of the largest and oldest individuals observed; sketch in living state. 



2. Somewhat younger individual than above, with body-diameter measuring 

 about 1.5 mm; sketch in living state. The meridional canals are roomy and sac-like. The 

 tentacle-stem has not developed as yet. 



3. Individual with body -diameter measuring about i mm; sketch in living state. 

 The ribs have not developed as yet. 



4. Individual with body-diameter measuring about 0.5 mm; sketch in living 

 state. The gastro-vascular system is in a form of a connected pair of cavities each of which 

 is laterally divided into four peripheral pouches. 



