700 MacCALLUM. [Vol. XV. 



there. They are densely loaded toward the free margin with 

 granules and larger masses of a brown pigment. 



The ventral sucker is larger than the anterior, and is situated 

 somewhat deeply in the body of the worm, the margins appear- 

 ing rather depressed. The musculature is as usual made up of 

 three sets of fibers — an internal running in a somewhat tri- 

 angular course parallel to the inner surface of the sucker, and 

 provided with a triradiate fibrous intersection (PI. XXXIX, 

 Fig. i) — a set of radial fibers making up the bulk of the sucker, 

 and an external layer disposed in fasciculi over the surface of 

 the sucker. The radial fibers sometimes cross in their course 

 from the outer to the inner wall. In the external layer there is 

 a fibrous point near the center, from which the fasciculi radiate 

 backward ; in front of this, however, they arch irregularly in 

 a transverse direction. 



There are no peculiarities in the arrangement of the body 

 musculature ; longitudinal, transverse, and two diagonal layers 

 are present in their usual relations. There is, however, a reen- 

 forcement of the transverse layer in the neck region. The 

 skin is quite unarmed and smooth, and I have been able to 

 observe none of the transverse striations spoken of by some 

 authors (Rudolphi (i), etc.). It is probable that this appear- 

 ance was given by the delicate canals of the watervascular 

 system, which form a rich network in the subcuticular tissues. 

 The gland-like cells which lie under the superficial musculature 

 seem more than usually numerous in this species, and form a 

 thick layer. The parenchyma in the anterior portions of the 

 body is made up of large oval cells with large round nucleus 

 provided with a deeply staining nucleolus (PL XXXIX, Fig. 5). 

 The protoplasm of these cells is very granular, the granules 

 taking on a sharp eosin stain. In the posterior parts of the 

 body the structure of the parenchyma is less apparent, and the 

 definite cell bodies give place to a vacuolated reticular formation, 

 with smaller scattered deeply staining nuclei. 



The watervascular system is made up in this form of four 

 parts — the ciliated funnels giving rise to fine tubules, the 

 cihated canals forming the subcuticular network, the lateral 

 canals, also ciliated, and the paired caudal reservoir with the 



