Reproductive Organs of Spams Centrodontus. 33 



FE:yiALE — The urinary bladder resembled that of the male. 

 It is on the right side of the mesenter3^ In four females the bladder 

 contained white granular fluid. The inside of the bladder was longi- 

 tudinally ridged. 



Testis. 



In fishes measuring from 42 to 45 cm. in length in January the 

 testis was large and white. A dra^^'ing of the testis in natural size is 

 given in Fig. 112. The vas deferens is a thick-walled tube, apparently 

 muscular. 



In two fishes measuring 37 and 43 cm. in length the testis, 

 although white, was small. 



In February some of the testes were ripe in fishes measuring from 

 40 to 46 cm. in length. They contained milt of a white pasty nature. 

 The vas deferens was distended with milt. 



One fish in March measiTred 45 cm. in length. It had a white 

 testis. 



The Ovarii. — Januani, Fehruary. March. 



A general view of the ovary and its connections is given in natural 

 size in Fig, 111. The ovary is remarkable : it is a long, narrow, 

 flaccid organ. Its anterior end is bent on itself. It exhibits on its 

 external surface a good deal of black pigment. If the outer wall be 

 slit open (Fig. 108) the true ovary (lav.) is found lying loose within, 

 except for the attachment to the skin formed by the blood vessel (hv?) 

 at the anterior end. The ovary was dark red : it was well supplied 

 with blood vessels. The line along which the mesentery is attached 

 on the outer surface is indicated by the groove {gro., Fig. 108). In the 

 preserved condition the ovary was flattened : it was of one breadth in 

 its whole length. The internal surface of the sac is ridged with 

 longitudinal muscles. In some of the ovaries the outer wall was 

 slack. 



The united oviduct is opened to show the junction of the right and 

 left oviducts (r. ovd, I. ovd, Fig. 111). 



If the ovary be cut across, it is found to consist of a thick rind which 

 encloses a space occupied by a loose network tissue (Fig. 107). In 

 this central space two large blood vessels, an artery {ar) and a vein (hv) 

 are to be seen. They break up into a network of vessels that fills up 

 most but not all the space. Yellow gland-like bodies are present at 



The rind consists of a basement layer supporting columns or septa 

 filled with eggs. Each column has two layers of eggs, between which 

 is the principal blood vessel. At the ends of the columns a few eggs 

 project on little stalks ; thej^ are becoming yolked. 



An enlarged drawing of a portion of a column is shown in Fig. 102. 

 The basement laj^er consists of round nucleated cells, accompanied by 

 branching vessels, some of which have rigid walls, and therefore stand 

 open. Some of the vessels had csecum-like branches. Each ovum is 

 contained in its own skin, and is supplied with blood vessels that go 

 between the eggs. Some of the fibres on the inside of the column were 

 wavy : they ai'e probably muscular. Fig. 101 shows a theoretical 

 section of a column. The column appears to be a sac enclosing two 



