Or 
STUDIES ON THE TURBELLARIA. 42: 
Studies on the Turbellaria. 
By 
W. A. Haswell, VE.A., D.Sc., F.R.S., 
Challis Professor of Biology, University of Sydney. 
PARTS I anp II. 
With Plates 25—27. 
Part I.—On Heterocherus, an ‘‘ Acelous”’ Turbellarian. 
Introductory—Occurrence— External Features— 
Movements.—The genus Amphicherus was founded by 
von Graff (15) for a species previously (13) named by him 
Convoluta cinerea. A nearly allied North American form 
was described in 1892 by E. L. Mark (20), and further details 
of its structure, with an account of its development, were 
subsequently published by Gardiner (9 and 10). 
The feature which was originally supposed to distinguish 
Amphicherus from all other members of the family 
(A phanostomida) to which it belongs, was the presence of 
a bursa seminalis containing two chitinous “ mouth-pieces,” 
but forms nearly related to A. cinereus, and regarded as 
referable to the same genus, have been found by von Graff 
(16) to possess a number of such chitinous parts. Poly- 
cherus, the genus described by Mark, has many chitinous 
mouth-pieces in the bursa, but it differs from all the known 
species of Amphicherus in having distinct vitellaria. In 
this latter point the form to be now dealt with differs from 
Polycherus, and agrees with Amphicherus, but in the 
vot. 49, PART 3,—NEW SERIES, dl 
