33] LIFE HISTOR Y OF TREAT A TODES—FA UST 33 



not to be confused with them. The cystogenous glands function in the for- 

 mation of the larval cyst at the time when the transfer to the secondary or 

 definitive host is to be made. Genital glands, in the sense employed here, 

 include only the auxiliary gland elements of the genital system and do not 

 refer to the sex glands themselves. Locomotor glands arise in connection 

 with the locomotor organs in the posterior part of the body. 



The dermal glands are of adult significance. Looss (1894:125) has found 

 them in all groups of adult trematodes studied, but he does not later (1896: 

 219, Fig. 176, glcu) record them for any cercariae except C. vivax Sons. 

 No dermal glands have been found by the writer in the course of the present 

 study. 



Salivary glands are probably present in all groups of cercariae and in 

 some rediae. In the simplest form they are nothing more than pyriform cells 

 in the region of the digestive tube. Thus the monostome cercaria, C. imbricata, 

 described by Looss (1896:195) as having a pharynx without a bulb, has unicell- 

 ular glands massed around the tube in the pharynx region. The f urcocercariae, 

 with no true pharynx, have a similar group of cells in the pharynx region, 

 so closely massed together as to lead Looss to considering them a true pharynx 

 (1896:220, Fig. 176, ph). In structure these masses of glands in the furco- 

 cercariae look superficially like a pharynx (Fig. 142), but on cross- 

 section the cells of the complex are found to be unmistakably glandular 

 (Fig. 152). 



A modification of the type of salivary gland just described has been ob- 

 served in Cercaria micropharynx, C. diaphana, and C. glandulosa. In these 

 species the cercariae show not only the muscular pharynx, but also a large 

 group of gland cells around the digestive tract. In C. micropharynx (Fig. 93) 

 the glands are prepharyngeal, grouped in a spherical mass around the oral 

 chamber. They are minute cells, about 3/^ in trans-section. The glands of 

 C. diaphana (Fig. 76) exhibit a maximum glandular growth in the vicinity 

 of the pharynx proper. Several hundred gland cells about 3/i in diameter 

 surround the pharynx. A case of secretion along the entire digestive tract 

 is found in C. glandulosa (Fig. 60). In this species the glands are much larger 

 than in the two preceding species, about 6/i in cross section and 12/^ to 25^* in 

 length. They are formed along the entire course of the lumen, from the ori- 

 fice to the blind end of the ceca, altho the}^ are best developed in the region of 

 the pharynx. 



A distinctly different type of gland is that termed the "stylet gland." 

 It is so-named because of its frequent occurrence coincidently with the stylet 

 organ of the xiphidiocercariae. But since it occurs, too, in furcocercariae 

 and in echinostome cercariae, where there is no trace of a stylet, the evidence 

 supports the view that this type of gland is more generalized and more primi- 

 tive than the stylet organ. 



These glands are found in the cercariae of the distome groups examined 

 by the writer, and in the redia of the holostome, C. flahelliformis . They are 

 bilaterally symmetrical, lying outside the intestinal furcae, behind the region 



