No. I.] SPHYRANURA OSLERT. 47 



muscular pharynx, mp. It passes through the anterior arch of 

 the intestine ; m, radial muscles of the upper lip ; g, ganglion- 

 cells; r, a renal cell; x 165. 



Fig. 7. — Diagram of the nervous system of Sphyranura 

 from the ventral surface ; Ig, lateral ganglion, opposite the 

 suprapharyngeal commissure ; ic, infrapharyngeal commissure ; 

 /, lateral ; vl, ventro-lateral nerve-cords with their commissures c' , 

 pec, the precaudal, and cc, the caudal commissures. 



Fig. 8. — a, ganglion-cell from Flemming's fluid preparation; 

 by transverse section of process of a ganglion-cell; x 1000. 



Fig. 9. — a, muscular fibre from caudal lamina of a fresh 

 specimen treated with chloroform ; b, muscular fibre fixed in 

 contraction; X 1000. 



Fig. 10. — From a horizontal preparation, like Fig. 6, near 

 the caudal lamina ; a, b^ superficial and deep layers of the 

 investing membrane ; c, circular ; d, longitudinal muscles ; e, 

 muscle-nuclei ; f, and h, cells of the parenchyma ; g, renal 

 cell ; X 600. 



Fig. II. — Intestinal epithelial cell from similar section ; X 

 1000. 



Fig. 12. — a, renal cell fresh in connection with a vessel 

 filled with granules ; b, renal cell, fresh ; c, from a Flemming's 

 fluid preparation ; d, ciliated funnels ; x 800. 



Fig. 13. — Diagram of the female genital ducts; rs, the 

 receptacula seminis, the ducts from which are joined by those 

 from the vitellogen before they communicate with a reservoir in 

 the middle line, which opens by a constricted passage into the 

 strongly ciliated ootype {00). Into this there open the ducts 

 communicating with the uterus {u) and ovary {ov), as well as 

 the overflow-tube into the intestine, the mouth of which is 

 indicated by the *. The arrows show the direction of the ciliary 

 movement. 



Fig. 14. — From a transverse section; d, dorsal; •z/, ventral 

 surface ; vn, In, ventral and lateral nerve-cords ; vd, vas 

 deferens ; vi, vitellogen ; p, parietal cells of a testicular lobule, 

 which is filled with sperm-cells in various stages of develop- 

 ment; X 220. 



Fig. 15. — a, parietal cells of testis; one of these is dividing; 

 b, first stage in formation of a sperm-sphere ; c, a sperm-sphere 

 with segmentation-cavity; d, a sperm-sphere with elongated 



