76 Illinois State Laboratory of Natural History. 



EXPLANATION OF THE EIGURES. 



PLATE I. 



Fio. 1. — Longitudinal vertical section through the anterior part 

 of the body, a, Pharynx, h, (Jizzard, showing the two thick bands 

 of transversely disposed muscle of which its walls are largely com- 

 posed, c, Gi^sophagus. d, Cerebral ganglion, e, Ventral nerve chain. 

 /, Two of the thickened muscular septa. 



Fig. 2.— Anterior part of the alimentary canal, a, Pharynx, 

 with radiating bands of muscle, b, Gizzard, c, (Esopliagus. d, Swol- 

 len beginning of intestine, e, " Prostate glands." 



Fig. 3. — Anterior part of the dorsal vessel and part of the genital 

 organs, a, Dorsal vessel, b, Two of the large " aortas", c, One of 

 the small contorted afferent blood vessels, d, Spermatheca;. e, Sem- 

 inal vesicle ( ?). /, Testicle, g, Ovary. 7i, Oviduct. 



PLATE II. 



Figs. 4-9. — Cross sections of the pharynx, showing tlie manner in 

 which the dorsally situated tongue extends into the cavity of the 

 pharynx, a, Pharynx, b, Xerve cord which supplies integument in 

 region of prostomium. c, Tongue, appearing as a slight dorsal fold 

 in Fig. 6. and becoming gradually larger and more muscular pos- 

 teriorly, as in Fig. 9. d, Cerebral ganglion, e, Subpharyngeal 

 ganglion. 



Fig. 10. — Cross section of the muscular gizzard. 



Fig. 11.— Dorsal view of the prostomium and the six anterior 

 somites. 



Fig. 12.— Ventral view of somites 13 20, showing tiie clitelhim 

 on somites 13-18. a. External aperture of the oviducts, b, One of 

 the anterior copulatory papilUe. c, Copulatory seta; and aperture 

 of "prostate gland", d, External aperture of vasa deferentia. 

 e. One of the posterior copulatory papillae. 



PLATE III. 



Fig. 13.— Cross section through the intestine, a, Dorsal vessel. 

 b, Intestine, b, Typhlosole. d, Subintestinal blood vessel, e, Ventral 

 nerve chain. /, Sections of small contorted afferent blood vessel. 

 g, Cuticle of integument. //, Ilypodermis. i, Circular muscle layer. 

 j, Longitudinal muscle layer. 



Fig. 14. -Part of the wall of the intestine greatly enlarged, a, 

 Ciliated intestinal epithelium, b, Coagulated blood occupying sin- 

 uses between epithelium and circular muscle layer (c) of intestine. 

 d, Longitudinal muscles of intestine, e, iJands of tissue extemling 

 across sinuses from epithelium to circular muscle layer. /, Connective 

 tissue layer. 



