232 CHAS. W. HARGITT. 



EXPLANATION OF PLATE IX. 



FIG. I. Photograph of section of egg under one-twelfth oil immersion, showing 

 the crescent of pigment granules extending peripherally from the nuclear region. 

 This area is very imperfectly shown as compared with the actual condition as seen 

 under the microscope. 



FIG. 2. Photograph of section of an egg about the period of beginning maturation. 

 The flattened nucleus at the outer margin is evident, as is also similar change in the 

 nucleolus. There may also be observed the general dissolution of the nucleus. Mag- 

 nification as in Fig. I. 



FIG. 3. Photograph of section through two eggs in a single gonophore, showing 

 the flattening of the eggs along the line of contact. The cleavage masses may be 

 observed as about the same stages in each egg. While this is often the case, there 

 are exceptions, as shown in some of the text figures. 



FIG. 4. Section of egg photographed under one-twelfth oil immersion, showing 

 the more or less syncytial character of the egg at this stage of development. 



FIG. 5- Section through a male gonophore, showing on one side the egg, and on 

 the other the mass of spermatozoa, with the body of the spadix occupying the median 

 region of the section. 



FIG. 6. Photograph of portion of an embryo about ready to be liberated, showing 

 the entoderm and ectoderm well differentiated, and with cell-like masses of pig- 

 mented yolk spheres in the enteron. It may also be observed that the ectoderm is 

 practically free of pigment matter, as pointed out in the text. 



I am under obligation to my colleague, Dr. Rogers, for the photo-micrographs 

 illustrating the above features. All were made under the one-twelfth oil immersion 

 lens, with arc light illumination. 



