104 
46A. 
465. 
460. 
47. 
48. 
CALIFORNIA ACADEMY OF SCIENCES. 
PLATE XXXVI. 
PONTODRILUS MICHAELSENT. 
Section through the rudimentary gizzard or thickening of the intestinal wall in somite v. 
One of the circular muscular strands of the former figure. 
Section of the alimentary wall adjoining posteriorly to the rudimentary gizzard in somite vi. 
A longitudinal section through the intestine showing the glandular-crop in somites xiv, xv, xvi, and the be- 
ginning of the sacculated intestine in xvii. d.v. dorsal vessel. d.v.c. connection between the dorsal vessel 
and the vascular system of the crop. gl. cr. glandular crop.  /. s. blood sinus in the outer layer of the 
glandular layer. gl. c. glandular cells constituting the bulk of the crop. clo. chloragogen cells. m. 1. the 
two muscularlayers. ¢.7. the end of the tubular intestine or cesophagus. 
A section of the former more highly magnified, showing the glandular cells which constitute the crop and the 
branched lumens which are especially pronounced in the outer part of the layer. /.m., ¢. m. the two mus- 
cular layers, which here are not more developed than in any other part of the intestine. 
Cross-section through the glandular crop in the posterior part of the organ in somite xvi. In this section only 
few of the glandular cells are found. 
A section anterior to the former, but inthe same somite. Here many more of the glandular cells are seen. In 
these two sections the chloragogen layer is thick and the cells crowded, similarly the ridges of the epithelial 
cells ave high and separated by deep grooves. 
A similar cross-section through the crop in somite xv. Both the chloragogen cells and the epithelial cells are 
lower. 
Another cross-section showing the entrance of a blood vessel from the dorsal vessel into the vascular system 
of the glandular crop. 
A part of the glandular cells of the crop more highly magnified showing the structure of the cells and the 
branched lumens between them. g/l. c. glandular cells. /. lumen. 6/. blood sinus. ep. inner epithelial 
cells. 
An oblique section through the surface of the crop showing the two muscular layers, a blood sinus and a few 
chloragogie cells cut through. The glandular cells immediately below are not delineated. 
