STUDIES OX THE ECTOPARASITIC TREMATODES OF JAPAN. 39 



syiicvtiiiin (PI. X^'T^. fig. (>). They are distributed, botli on the 

 ventrnl and dorsal sides (PI. XVII. fig. ")). into two groups, the 

 right and the left ; and the cells of each group discharge their jtroducts 

 into a common large dur-t" ])rovided with a distinct membrane. whiHi 

 onens l)v a minute aperture on the ventral sui'face of the lateral poi'tion 

 of the body, at a sliort distance from the stalk of the sucker (JM. 

 X^ II. fig. 12, (jV). The secretion of these granular cells is a very 

 granular fluid, the granules staining very deeply in haematoxylin. 



Tristominn and Epibdella — As has already been observed l)v 

 Monticelli,-^ there are, in these genera, numerous unicellular glands 

 in the anterior portion of the body ; and in some species of Trist omwn 

 (T. siuuatvm and T. hipamsiticum) there is in addition a series of 

 groups of unicellular glands whi<"h open at regular intervals along 

 the lateral borders of the l)ody. 



The cells of the anterior stickv "lands are more or less iroblet- 

 shaped, with a very thin memlirane, a more or less granular cyto- 

 plasm, a nucleus with a single nucleolus, and a long neck. The 

 nucleus sometimes occupies the central position, l)ut is sometimes 

 (piite peripheral. The cells are distributed almost uniformly, or in 

 grou|)s separated from one another l)y dorso-ventral muscular fil)res, 

 iri the mesenchyma of the suckers and of the anterior, median portion 

 of the body. In some species of Tn'slonuini (as in T. ovale) the necks 

 of the gland-cells open at various points on the ventral surf ice of the 

 sucker, at the tops of small, conical papillae (PI. XXII, fig. 5), and 

 especially along the inner border of the sucker, where the papillae are, 

 as already mentioned, larger and very numerous (fig. 5). In T. 

 sinuatinii the glands open mainly along the margin of the ariterior 



1). Its size, however, proliably varies according to the quantity of its content. 

 2). Monticelli— Di alcuni organi di tatto nei Tristomidi : Sollet, delta Soc. di Xatviralisti 

 in Xapoli, Ser. 1, Anno 5, vol. V., 1891, fas. 2. 



