120 PROCEEDINGS OF THE ACADEMY OF [Feb., 



already been mentioned. There remains to be described the "salivary 

 glands" (Speicheldriisen, O. S. Schmidt), and a set of huge glands which 

 I have termed "cephalic glands." The description of these latter 

 glands is brought into this section not so much because of their hypo- 

 thetical relation to the digestive system, as for the sake of convenience. 



The salivary glands (fig. 5, s.gl.) are similar to those of D. gyrociliatus 

 (Schmidt, 1856; Repiachoff, 1886) and D. apatris (Korschelt, 1882). 

 They consist of two groups of large unicellular glands, each group num- 

 bering in the neighborhood of a dozen cells, situated laterad to the 

 oesophagus, in the angle formed by the junction of the latter with the 

 stomach, and forming an ovoid or pyriform mass. The cytoplasm of 

 these gland cells stains from a brownish yellow to a deep black in iron- 

 hsematoxylin, and has a homogeneous, compact appearance, but 

 frequently encloses vacuoles of a lighter tint. The nuclei are spherical 

 and contain large nucleoli. From each cell proceeds a slender duct, 

 which passes along each side of the horizontal limb of the oesophagus, 

 in contact with it, the ducts of each side uniting to form a bundle (fig. 

 4, s.gl.d.). Arriving at the ascending limb of the oesophagus, each 

 bundle splits up into its component ducts. These enter the cesophagus, 

 penetrating between the cells of its lateral and posterior walls, each at 

 a different point, and open into its lumen (fig. 3, s.gl.d.). In D. 

 apatris these glands are said by Korschelt to open between the oesopha- 

 gus and proventriculus. In D. gigas (Weldon, 1886) gland cells are 

 found lying outside of the pharangeal (oesophageal) wall, while similar 

 glands lie at the base of the hypodermis forming the outer lips. Har- 

 mer (1889a) describes "racemose" salivary glands opening into the 

 anterior division of the oesophagus. Schimkewitsch (1895) says of the 

 salivary glands of D. vorticoides: "sie offnensich mit einigen Blindeln 

 der ganzen Osophagus entlang seitlich und naher zum Rueken." He 

 also speaks of them as "mit Mucin erfiillt." It is quite evident that 

 in D. conklini the contents of these glands is not mucin, although 

 staining densely in hsematoxylin, for in all of my preparations which 

 were stained in Meyer's mucicarmine, a specific mucin stain, not one 

 of these glands is tinged with it in the slightest degree, while the 

 hypodermal mucous glands are all deeply colored. 



The cephalic, like the salivary glands, form two groups or complexes 

 of large unicellular glands. These are situated in the dorsalmost 

 portion of the head cavity, just in front of the vertical limb of the 

 oesophagus, each group symmetrically disposed a short distance on 

 either side of the midline (see text fig. Ill, A. and B). Each gland 

 cell, of which each group contains three to five, is pyriform in shape 



