PACIFIC COAST OLIGOCH^TA. 77 



perfectly enclosed in the glaiuliilar layer, forming generally a row of vascular 

 lacunes near its outer margins (fig. 48 hi. «.) apparently without touching the mus- 

 cular layer, or doing this only at certain places. Figs. 49 to 53 represent cross-section 

 from different parts of the crop, from the posterior part, near the boundary of somite 

 xvii (fig. 49), to the anterior part of xiv (fig. 52), illustrating the variations in thick- 

 ness of the glandular layer. In the posterior part this layer is very thin (fig. 49 yl.) 

 consisting only of a few cells, from one to three cells wide. \n figs. 50 to 52 the 

 glandular layer is seen to iiave increased in thickness and so has the inner epi- 

 thelial cells. Fig. 53 is a portion of the glandular layer, in which the inner lumen 

 is more plainly represented. The outer part of this glandular layer is divided up in 

 lobes by the numerous blood sinuses, and in each such lobe there is a wider or nar- 

 rower, generally, branched lumen, which, however, I have not been able to follow 

 down to the epitiielial cells. 



The sacculated intestine commences at the posterior end of the cro[), and 

 offers nothing of great interest or characteristic. 



There is no thyphlosole, but the intestine is otherwise very rich in blood 

 lacunes. 



Pharyngeal ov Salivary Gland. Pharynx which occupies somites ii and iii is 

 only developed dorsally. It is superposed by a large mass of glands and muscles, as is 

 usual in a large number of 01igoch;tt;e. In outline this glandular mass is remarkably 

 even, especially so at its posterior end. In a longitudinal section we see customarily 

 three lobes (fig. 29), supported by long strands of muscles, running back to the pos- 

 terior boundaries of somites vi, vii and viii. 



On the ventral side there are seen three of those muscular strands, similarly 

 running back to vi, vii and viii, indicating that there is a row of similar strands corres- 

 ponding with somites ii, iii and iv. In somite v there is a pair of smaller glands of 

 similar nature attached to muscles which connect with the larger strands of the main 

 gland (fig. 29, s.s. gl.) 



A cross-section of this glandular mass (fig. 30), shows us that the glands are situated 

 principally on the periphery, supported by muscles (ww.), while the inner and posterior 

 part is principally taken up by strands and ducts. A division of the mass in three more or 

 less distinct layers is discernible, probably corresponding to somites ii, iii and iv. These 

 glands communicate directly by means of ducts with the epithelium of the j^hfxrynx. 

 In fig. 29 these ducts are roughly represented as dark violet. In the cross-section 

 (fig. 30), the darkest blotches are intended to represent the ducts, while the lighter 

 colored violet ones are the glands. In fig. 31 a lobe of the longitudinal .section is seen 

 in a larger magnification, and in fig. 32 a smaller lobe, yet more highly magnified. 

 The glandular cells are rather of varying size, and arranged around the margin of 

 glandular sack, leaving the inner space open. The cell cytoplasm is massed in places, 

 leaving in other places larger or smaller, generally roundish, vacuoles (fig. 35, va.) 



In figs. 33 and 34 I have endeavored to show the relative arrangement of the 

 muscular strand.s, the glandular ducts and the glandular cells. As will be seen these 



