156 BULLETIN OF THE 



of secretion from the gland as a whole stand in strong contrast with the 

 resting and active stages in secretion as found in the bicelhilar glands. 

 The function of the secretion from the multicellular glands is probably 

 more general, since the glands are so uniformly distributed over the sur- 

 face of the body.^ 



One of the most peculiar points in connection with these glands is 

 their relation to the nervous system. In almost every instance, a nerve 

 fibre can be clearly traced from the subdermal plexus to the proximal 

 end of the gland, and on fortunate sections (gl.'" n./br., Fig. 14) it was 

 possible in a number of cases to demonstrate an actual connection be- 

 tween gland cell and fibre, in that the former was prolonged into a deli- 

 cate fibril, which, passing out from the glandular cavity in company with 

 similar fibrils from the adjacent gland cells, entered within the neuroglia 

 into the substance of the nerve and appeared to make up its fibrillar 

 structure. This connection of gland cell with nerve fibre is found in 

 all regions of the body, and is not confined, as Andreae maintained, to 

 the posterior tip (Eichel) of the animal. In spite of this direct nervous 

 connection, there seems to be little ground for regarding these struc- 

 tures as sensory organs, the interpretation put upon them by Leydig 

 ('61) and others after him. A careful examination brought to light 

 only the single kind of cells, which are in no way comparable with 

 sensory cells. On the other hand, it may be said that a rich nervous 

 supply is not without parallel for glandular structures. 



The capsules of these glands are very thick, and nuclei are found on 

 the partitions between the cells, showing that each cell is enclosed in a 

 separate investment. But the partitions are never as strong as the gen- 

 eral sheath of the entire gland, which possesses nearly the optical appear- 

 ance of muscular elements. The variations in size are so great, being 

 from 40 X 50 /a to 90 X 150 /a in the same region of the body, that the 

 probability of a muscular capsule suggests itself strongly. 



Allusion has already been made to the relation of the glands to the 

 papillae. In each papilla of the posterior zone, one finds at its tip an 

 indefinite crowded mass of multicellular glands, and in an irregular 

 double or triple row across the basal half, the bicelhilar variety. All of 

 these open upon the external convex surface of the papilla. That the 

 relation of glands to papilla is an intimate one, first appears clearly from 

 the formation of the latter. As it is evident that new papilla) nuist be 

 added with the gi-owth of the animal, it is of interest to note the steps 

 in the formation of these structures. The first indication is an evident 



1 See Addendum. 



