218 H. GRAHAM CANNON 



Centrally these vacuoles coalesce and form an irregularly flat, 

 ill-defined reservoir (PI. 10, fig. 9). The vacuoles are not very 

 transparent, and in passing from the proximal glands to these 

 two cells of tlie distal glands one can see the \acuoles becoming 

 mor(^ opaque. 



The nuclei are not cup-shaped as Cunnington (5) stated to be 

 the case generally with the nuclei of the distal glands, but are 

 roughly spheroidal (PI. 10, fig. 9). Their diameter is not usually 

 so great as the length of the largest nuclei in the proximal 

 group, but there is probably not much difference between the 

 volumes of these nuclei. There are larger clumps of chromatin 

 in the nuclei than in those of the proximal group, and also the 

 nucleoli, which stain red with Mallory's stain, are about twice as 

 large. But there is also a diffuse scattering of chromatin all 

 through the nucleus which gives it a much darker appearance 

 in a stained preparation. 



These two anterior cells of the distal group are connected by 

 an attenuated process with the two posterior gland-cells 

 (Text-fig. 1 ; PI. 10, fig, 13). The reservoir in the anterior 

 pair is not continuous as a duct through this drawn-out con- 

 nexion, but vacuoles are to be seen here, so that presumal)ly 

 the secretion can pass from the anterior to the posterior pair 

 of cells. This connexion is always attached to the dilata- 

 tor as oesophagi (PI 9, fig. 4), and its middle point is 

 a httle posterior to the labral nerve loop (Pis. 9 and 10, figs. 4 

 and 13). 



The nuclei of the posterior pair of gland-cells are cup-shaped, 

 as Cunnington states. Most of the nucleus forms a thin lamella 

 but there is usually a swelling in the region of the nucleolus 

 (PI. 10, fig. 12). This is large and usually flat and shows the 

 same staining reactions as the nucleoli of the other gland-cells. 

 The chromatin is gathered together in clumps as shown in 

 PI. 10, fig. 10, but a more irregular clumping as shown in 

 PI. 10, fig. 12, is more characteristic. 



The cytoplasm is pervaded with vacuoles of secretion which 

 are opaque to varying degrees, and these are very conspicuous 

 in the hemispherical recesses formed by the nuclei. As before, 



