Il8 ANDREWS. [Vol. V. 



closely packed in a common protoplasmic mass (Fig. 5). Im- 

 mediately about the blood capillaries the nuclei remain small, 

 (Fig. 7, a), while towards the periphery of the mass they increase 

 in size and often show a linear arrangement (b), and then when 

 still larger exhibit cell boundaries (c). In these faintly outlined 

 cell strings, while part of the solid ovarian matrix, certain cells 

 increase in size, and may be recognized as ova (ov). Such linear 

 series of cells become detached from the general matrix except 

 at the tips, and so form loops or cell strings projecting more 

 and more freely from the solid part of the ovary. Eventually, 

 such cell loops (Fig. 5) break away even at the tips, and then 

 float off in the body-cavity liquid, each with a growing centrally 

 placed ovum. 



In certain parts of the ovarian matrix nuclear division appears 

 to take place actively, but neither this nor the subsequent linear 

 arrangement of nuclei and cells could be referred directly to the 

 arrangement of the blood-vessels around and upon which the 

 ovary is, as it were, built up. 



In the males of both species the body cavity may be filled 

 with spermatozoa and the masses of cells giving rise to them, 

 but no strings of cells comparable to those of the female are 

 found. The testis has the same position and relation as the 

 ovary, and is also to be regarded as a mass of peritonaeal cells. 

 It may, however, be distinguished from the ovary by the size 

 and arrangement of the cells or nuclei, which in both species 

 are uniformly about 7 fi. in diameter, with nuclei 5 fi., and pre- 

 sent no such linear arrangement as is conspicuous in the 

 peripheral part of the ovary. The nuclei are thus noticeably 

 larger in the testis than in the ovary, excepting the older nuclei 

 of the ova themselves. 



The method of formation of spermatozoa was studied in pre- 

 served specimens in which sections show various stages inside 

 the body cavity. Though the nuclei are not arranged in linear 

 series in the testis, they grow out from its surface into the body 

 cavity as irregular, many-celled processes, which break off and 

 float free as clumps of generally but few cells (Fig. 8, a). By 

 division and multiplication of these few nuclei, characteristic 

 clusters about 55 /x. x 18 /a. X 37 fx. are formed, having an 

 elongated, somewhat flattened ellipsoidal form, and made up of 

 many small nuclei surrounded by little protoplasm (b). These 



