30 bulletin: museum of comparative zoology. 



The epithelium of the glandular portion consists of large polygonal 

 cells (Plate 4, Fig. 33), containing large oval nuclei. The granular 

 cytoplasm is confined to the base of each cell, where it forms a dense, 

 deeply staining mass; the portion of the cell adjacent to the lumen of 

 the gland contains a clear non-staining substance, which sometimes ap- 

 pears to occupy large vacuoles and is probably secreted fluid. A delicate 

 chitinous intima may be distinguished as well as a thin basement mem- 

 brane. The dorsal wall of the gland proper is connected to the ventral 

 wall of the maxillary pocket by columnar cells (Fig. 33) with small oval 

 nuclei and fibrous cell body. These are probably modified hypodermis 

 cells ; between them may be seen unmodified cells, which are flattened 

 against the cuticula. 



Transverse sections show the evacuating duct to be chitinous through- 

 out its whole length (Fig. 34), the component cells being indicated by 

 small, round nuclei only. The basement membrane is thin, but the 

 chitinous intima is thick. 



In my account of the anatomy and function of the principal cephalic 

 glands, I difl'er widely from Fernald ('90) and also from Willem et 

 Sabbe ('97). According to Fernald ('90, p. 63), a curious anatomical 

 relation exists between the " salivary glands " and the ventral tube or 

 " vesicle " of Anurida maritima. I give the author's own words : " Pass- 

 ing forward [from the cleft of the abdominal vesicle] on the ventral 

 median line of the body to a median cleft in the lower lip is a small 

 tube, in the formation of which both hypodermis and cuticula take part. 

 In the posterior portion of the head are a pair of glands which resemble 

 salivary glands and which I regard as their homologues here. From 

 these glands a duct leads forward and soon fuses with its fellow, and the 

 median duct thus formed passes along the under surface of the buccal 

 cavity to a median cleft of the lower lip, where, instead of emptying into 

 the mouth, it turns downward and joins the ventral tube just described. 

 This remarkable relation of the parts concerned I am unable to explain, 

 although sure that no error of observation w^as made." 



Willem et Sabbe ('97, pp. 131, 132) have recently offered an explana- 

 tion of ll^e peculiar relation which Fernald described but left without an 

 interpretation ; they claim that the ventral tube of Smynthurus is an 

 adhesive organ, covered with a glutinous substance and add : " Ce liquido 

 est secrete, comme Ta annonce Fernald pour Anui-ida maritima, par deux 

 glandes situees dans la tete, chez Sminthurus fuscus, elles sont logees dans 

 la region posterieure de la cavit6 cephalique et occupent les protube- 

 rances verticales posterieures de la tete. Chacmie d'elles est constituee 



