-39- 



(Flgs, 9 a and 9 b). Eaoh half of the gland Is a thin walled 

 ovoidal sac, about Scm, long and ^ tarn, in cross section. In the 

 sea lamprey. The epithelial cells of the v/alls are of a short 

 columnar form, and the walls are thrown into numerous Irregular- 

 ly-arranged papillae and short folds, v/hich project into the 

 cavity of the gland (Figs. 9 a and 9 b) . 



From the medial side of the gland, a short distance 

 back of its extreme anterior end, the duct leads forward, grad- 

 ually approaching its fellow of the opposite side, but never 

 meeting it, to open into the mouth cavity through a small papil- 

 la. Little or no secretion was seen in the gland. The posterior 

 end of the gland is separated from the first gill sac by a dis- 

 tance about equal to the space -coupled by t'.vo gil' sncs. 



Figure 9 a represents a transverse section through the 

 ventral part of the body of an adult brook lamprey. The large 

 basilar muscle (b.m. ) is seen on each side, betv/eon the body 

 wall (b.w.) below and the pharynx (phar.) above. Imbedded in 

 this muscle is the basilar or salivary gland (b.g.) whose walls 

 are thrown into irregular folds and papillae, as has been men- 

 tioned. 



Figure 9 b is anterior to 9 a and is drawn under greater 

 magnification. One side only of the gland is shown, the section 

 passing through it just anterior to the opening of the duct (d.) 

 into the gland. This figure shows that the folds In the wall of 

 the gland are formed by invaginations, of irregular form and at 



