Two New Trematodes of the Family Gyrodactylidse. 



penis. The transition between the duct and the glandular mass 

 is sudden. 



The ovary is a somewhat pyrifrom organ with a light con- 

 striction near its middle, situated directly in front of the testis, to 

 which its posterior border is closely apposed (fig. 1, 2, G). It is 

 a mass of egg cells in all stages of development and is enclosed by 

 a distinct membrane of connective tissue; the youngest ova are 

 found in the hindmost part and the most mature ones at the front 

 end, whence the oviduct takes its rise. The ovary and the 

 oviduct communicate with each other by an exceedingly small 

 opening which never appears in more than one section (5// or 

 less). The oviduct is a comparatively short and spacious canal, 

 lined with a layer of finely granular protoplasm, which varies 

 in thickness according to the degree of distention, but becomes 

 thicker near the ootype and contains a few vesicular nuclei; it is 

 provided with very fine circular muscle fibres. The oviduct is 

 separated by a light constriction from the fusiform ootype which 

 follows it and which has a wall similar to that of the oviduct, in. 

 which a few flattened nuclei are present. The ootype receives 

 the ducts of the numerous unicellular glands of Mehlis (fig. 1, 6, 

 10), which are unusually well developed and occupy nearly the 

 whole of the space between the intestinal cceca of both sides, 

 from the posterior prostate gland to the anterior end of the ovary 

 or further backwards. The cells are pyriform and very large, 53/^ 

 or more when at the height of their activity, when the contents 

 are coarsely granular and vacuolated and stain but faintly with 

 haematoxylin; the nuclei are large but have faint contour just 

 perceptible under the microscope (Zeiss objective E), and enclose 

 each a well defined chromatin mass. The ducts are especially 

 conspicuous in sections when the discharge is actively going on 

 and can be seen converging to the ootype, into which the 

 secretion appears to ooze through its wail. In the smaller 

 ones of these gland cells the cytoplasm stains fairly well with 

 haematoxylin and the nuclear contour is better defined. The 

 ootype leads in front into a short uterus opening into the 

 genital atrium from behind, close to the ventral surface of the 



