S. GOTO. 



by a fine line on the external surface of the investing membrane, 

 which usually stains in haematoxylin deeper than the subjacent layer ; 

 but its thickness is always very insignificant, and can not be measiured 

 with any approximation to accuracy even under the magnifying 

 power of 300 diameters. But that it is a distinct layer of cuticular 

 nature is clearly proved by the fact mentioned in my former paper, 

 that when any fresh specimen is observed in water under the cover- 

 glass for a suJBficient length of time, watery blisters are formed in 

 various parts of the investing membrane, and the cuticle is raised 

 from the subjacent layer. 



Next to the cuticle comes a layer of varying thickness, form- 

 ing my subctiticle. In its behaviour towards staining fluids, it is 

 somewhat different in different species, the difference, however, lying 

 only in the different intensity of its affinity with stains. For in- 

 stance, in Microcotyle and Onchocotyle it is but slightly stained, while 

 in Tristomum and Monocotyle it takes up the stain with greater avidity. 

 In most species this layer is more or less granular, the ground- 

 substance being formed by a uniformly stained, structureless substance. 

 This ground substance seems, in the fresh state, to be of a semifluid 

 nature in most cases, and of a greater density than water. This I infer 

 from the fact that when watery blisters are formed under the circum- 

 stances already referred to, the water seems to pass into the subcuticle 

 by a simple osmotic process and mix freely with its substance, — the 

 substance of the subcuticle being quite undistinguishable from the 

 water taken in. In Onchocotyle, the subcuticle appears striated in 

 cross-section, the striation being caused by numerous fibrillar structures 

 traversing it at right angles to its thickness. B&sides these fibrils, 



of Schwarze, Sohauinsland, and Biehringer, very few in number (C/. Monticelli — Studii sui 

 Trematodi endoparassiti : Primo contribute di osservazioni sui Distomidi. Spengel's Zoolog. 

 Jahrbucher, III. Supple., 1893.). 



