114 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



distinguished by their free extremities, which project into the 

 pharyngeal cavity in the form of conical papillae. Their 

 number varies according to the size of the individual, and 

 as far as could be determined ranges from about twenty- 

 five to fifty. In fully grown individuals, where these cells 

 are correspondingly large, they may readily be seen to 

 conform to the type of gland-cell which has been termed 

 " diakrinous." The major portion of each consists of 

 finely granular protoplasm, in which is imbedded a sharply 

 defined spherical nucleus, often with densely aggregated 

 chromatin and one or two comparatively large vacuoles 

 (fig. 6). Toward the free end of the cell the nature of 

 the protoplasm changes, losing its granular character and 

 affinity for stains and assuming a striated appearance. This 

 latter feature is due to a large number of intracellular canals 

 which connect on the one hand with the glandular portion 

 of the cell, and on the other with a minute reservoir. The 

 latter is often filled with a darkly staining secretion, and 

 may readily be followed to the cuticle, where it opens by a 

 minute funnel-shaped aperture. 



Other monogenetic trematodes have been described as 

 possessing somewhat similar papillae in the anterior half of 

 the pharynx; but in some cases, at least, they are said to 

 afford an outlet for the ducts from the cells (Kornerdriisen) 

 in the posterior half of the pharynx. The ducts from these 

 last-named elements often extend forward for a consider- 

 able distance, but in E . squamula I have never seen them 

 invade the territory of the diakrinous glands. 



The second division of the pharynx, devoid of papillae, 

 consists primarily of a number of gland cells (fig. 17, k^ 

 which probably correspond to the so called pharyngeal 

 glands (Pharyngealdriisen or Kornerdriisen) of a number of 

 other monogenetic trematodes. In most cases the proto- 

 plasm is compact, the nucleus dense and darkly staining, 

 and the ducts which lead to the exterior are short and 

 usually ill-defined. Among the cells of this nature are 

 often one or more of a spongy appearance with diffuse 

 nuclei, characters which appear to be due to the recent 



