128 JESSE LE ROY CONEL 



of the band of Myxine no. 12, shows another peculiar condition. 

 At the base of the band, in a pocket formed between the lobes, 

 there is a tangled skein of columnar epithelium which is of the 

 same width as the columnar epithelium around the band. Here 

 and there this skein is continuous with the epithelium which 

 envelopes the band. It extends through all the sections cut 

 in the posterior region of the testis band of Myxine no. 12, but 

 occurs nowhere else. The writer has been unable to explain 

 what this tissue may be. 



Myxine no. 12 and no. 13 are old animals, as is indicated by 

 their general conditions, viz., the thick, hard skin, the reddish, 

 coarse fibers of the muscular tissue, the enlarged, coarse, dark- 

 brown liver, the great diameter of the body, etc. The peculiar 

 condition of their testis . bands is interpreted as due to their 

 having become completely sterile with old age. Myxine no. 1*8 

 and no. 7, young, immature males, have many primitive germ 

 cells, a few follicles and very little connective tissue in the testis 

 band. Myxine no. 15, and adult male, has few germ cells, many 

 follicles, and much connective tissue around and between the 

 follicles in the testis lobes. In places the squamous epithelial 

 covering of the band has been converted into a columnar epi- 

 thelium, but sufficient squamous epithelium remains to permit 

 easy ruptiu-e of the folhcles when they are ripe. The band is 

 notched only slightly here and there. In specimens no. 12 and 

 no. 13 the germ cells and follicles have entirely disappeared, 

 and the bands are completely filled with fibrous connective tissue 

 and blood capillaries, and all the squamous mesorchial sheath 

 has been converted into a columnar epithelium. The testis 

 bands are deeply notched in all parts so that they are cut up 

 into lobes. The testis bands in these two animals have lost, their 

 power of functioning and are completely sterile. 



Bdellostoma 



Fe7nale. The generative organs of Bdellostoma closely re- 

 semble those of Myxine in many respects. The ovary is single, 

 occurring on the right side only, and is suspended in the body 



