480 WILLIAM A. HASWELL. 
VY 
EXPLANATION OF PLATE XX##, 
Illustrating Mr. William A. Haswell’s Paper “ On the Struc- 
ture of the so-called Glandular Ventricle (Driisenmagen) 
of Syllis. 
Fic. 1.—Anterior portion of the alimentary canal of Syllis a, magnified. 
@. Gisophagus. g. Gizzard. c¢. Cecum. 7. Intestine. pr. Protractor 
muscles. 
Fic. 2.—Transverse section of the gizzard of Syllis a (semi-diagrammatic). 
a. Peritoneal and external muscular layers. 4. Middle layer (striated muscle). 
ce. Annular band of non-striped muscle. 4d. Inner muscular and epithelial 
layer. 
Fig. 3.—Portion of a vertical longitudinal section of the gizzard of 
Syllis a, x 350. a. External muscular layers. 6. Striated muscular tissue. 
c. Finely fibrillated intermediate tissue with nuclei. d. Central protoplasm. 
e. Annular band of non-striped muscular fibres. The epithelium is diagram- 
matically represented. 
Fic. 4.—Transverse section of two of the muscle-columns of Syllis a in 
the outer portion, showing Cohnheim’s areas. xX 350. 
Fic. 5.—Transverse section of one of the muscle-columns of Syllis y, 
showing central protoplasm and Cohnheim’s areas. x 350. 
Fig. 6.—Portion of muscular fibre from the gizzard of Syllis a in the 
fresh condition. x 900. 
Fie. 7.—Portion of muscle-column of Syilis y, stained with hematoxylin 
and treated with glacial acetic acid, showing double transverse networks of 
Retzius and longitudinal networks. x 900. 
Fic. 8.—The same slightly teased, showing fibrillules into which the fibrils 
tend to break up. 
Fic. 9.—Portion of the striated muscle-fibre of Syllis a, preserved in 
alcohol, showing the projection of the bright substance as annular ridges. 
Fic. 10.—Portion of striated fibre of Syllis a, stained with hematoxylin. 
Fic. 11.—Fibrils of muscle of Syllis a, after treatment with 1 per cent. 
chromic acid for several days. x 900. 
Fie. 12.—Entire muscle-column of Syllis y, showing the external shape, 
the longitudinal cleft, and the central core. 
Fic. 13.—Longitudinal section of muscle-column of Syllis p. 
