218 
Taenia elliptiea 
effect of these two fixing agents on the tissues, fight was thrown 
on the relationship of the various structural elements of the body and 
on their nature. 
The anatomical arrangement of the structural tissues is as follows: 
A thickened structureless cuticle overlies a delicate basement membrane 
which surrounds the body. Within is a single layer of more or less 
elongated cells, lying perpendicular to the surface. These cells are 
connected with the basement membrane by branched processes, super¬ 
ficially, and by similar extensions internally they are directly continuous 
with the connective tissue parenchyma of the body and with certain 
dorso-ventral fibres described below. Between this layer of cells and 
the basement membrane, grouped in very small bundles lying between 
the superficial branched processes of these cells, is a delicate layer of 
longitudinal contractile fibres, called by me superficial longitudinal 
fibres. This layer is identical with a layer described by Hamann for 
T. lineata which he calls sub-cuticular muscles (1885, p. 718). 
Below the outer layer of elongated cells and connected with them 
is the connective tissue parenchyma of the body ; branched reticulated 
nucleated cells, in the meshes of which fie the various organs of the 
body. A central portion is however to some extent cut off from the 
external portion of the body by a layer of circular contractile fibres, 
thus dividing the body into three roughly equal sections, a dorsal, a 
central and a ventral section (Plate XVII, Fig. 1). Close outside this layer 
of circular fibres are a series of bundles of longitudinal contractile fibres 
forming a discontinuous layer of considerable bulk which must obviously 
exercise much power on the shape of the plastic proglottis and control 
the creeping movements of the free proglottides. Finally, throughout 
the body a great number of isolated dorso-ventral contractile fibres 
stretch from top to bottom of the body, and, branching superficially 
first into two and then into four tendrils, are connected with the 
internal processes of the outer layer of elongated cells. It is to be 
noted that these dorso-ventral fibres run through the bands of circular 
fibres, or even through a bundle of longitudinal fibres (Fig. 4) and are 
entirely independent of any other tissue or obstacle in their path. 
The superficial layer of elongated cells which one is at first sight 
tempted to regard as epithelial elements is surely not such. Their 
superficial as well as their internal branching processes, the layer of 
longitudinal contractile fibres outside them (s.l.f.), their intimate con¬ 
nection with the connective tissue parenchyma, the character of their 
nuclei and their contractile power, are all indications that they are 
