278 
FASCICULI MALATENSES 
trace them, they originate from seven main branches, which all arise in a 
semi-circle below the mouth. The course of one of the strands is indicated 
in fig. I, but it is not sketched direct from any one section, as it does 
not lie exactly, but only approximately, in the plane of the middle line. It 
runs, as will be observed, towards the posterior surface of the wall, and this 
seems always to be the case with the strands in both walls. Professor Weber 
states that contraction of these muscles causes the walls of the funnel to be 
drawn together, but, in my opinon, they have exactly the opposite function. 
Observations on the living tadpole have convinced me that the folded 
condition of the funnel is the condition of rest, and that its unfolding is due 
to a muscular effort, -and I think it is evident that if the muscles have the 
course I have indicated, their contraction will cause the basal part of the funnel 
to become rigid, and therefore to unfold itself, while the free extremity is 
probably flaccid under all conditions, being forced to straighten itself by 
external pressure as the tadpole rises to the surface. 
The epithelium which bounds the central mass is continuous with that 
of the general surface of the body, from which it differs in the absence of 
pigment granules and in its tendency, above, to form horny structures. It 
consists of small cells, five or six layers deep and generally approaching a 
quadrangular form ; their walls are well defined, their nuclei small. So far 
as I have been able to discover, there is no limiting membrane on the surface 
of the funnel. Blood vessels and blood sinuses do not occur in the epithelium, 
but it is possible to catch glimpses of minute branching nerves, which 
probably terminate, though I have not been able to trace them, in large, flask- 
shaped cells scattered singly on the surface. The latter are probably sensory 
in function, as their contents are not granular ; they have no connexion with 
the horny teeth. 
The structure and arrangement of these horny teeth differ considerably 
from those of the teeth of Pelohates fuscus^"' as well as the teeth of the 
Ranidae,^ for they are not connected in any way with definite ridges or 
depressions, but radiate out along the anterior surface of the funnel, and they 
are not, even in a limited sense, unicellular. They arise, however, in the 
epithelium, appearing on the surface as minute, conical, non-serrated horny 
bodies, beneath which the epithelium is distinctly arched over a corresponding 
prominence of the central mass. In what appear to be young teeth, a group 
of cells, lying immediately over the central mass, can be distinguished by 
their thickened walls. Higher, the walls have become definitely cornified. 
1. E. Gutzeit, Zeitschr. ‘zviss. ZooL, vol. XLIX, 1889, p. 50, pi. II, figs. 30-32. 
2. p. 46, and E. Schulze, Abhandl. Konigl. Preuss. Akad. 1888. 
