Reproduction of Eleutheria, Quatref. 3 
the lower side (distal surface of Hincks), and the opposite and 
more strongly arched surface as the back (proximal surface of 
Tiincks) *, 
The direction in which the furcation of the arms takes place 
has been, if not overlooked, at least not indicated with sufficient 
emphasis by Mr. Hincks. On careful examination, we shall 
soon be convinced that the knobbed branch, on quitting the main 
stem, stretches in a more or less inclined direction upwards and 
outwards, and that furnished with the sucking-disk downwards ; 
so that, when both come to stand in the same line, or, as is 
usually said, cover each other, the angle of divergence stands 
parallel or perpendicular to the axis of the body. 
The mouth is often seen extending itself in the form of a cy- 
lindrical tube, remarkable for its white colour ; and when this is 
the case, the otherwise only moderately convex lower surface of 
the body becomes more strongly inflated. This buccal tube, 
however, which is bent to and fro like a proboscis, not unfre- 
quently changes its form, sometimes assuming that of a short, 
wide-mouthed funnel, or even becoming inflated into a spherical 
shape. In this respect, therefore, it resembles the buccal cone of 
the Hydroid polypes, to which, and no less to the so-called 
stomachal peduncle of the Oceanide, it likewise corresponds 
morphologically. When the tube is extended, however often it 
may change its form, the mouth is always open; when the tube 
is retracted, the mouth closes completely. By this arrangement, 
the animal is evidently enabled to pick its food, which consists 
partly of Diatomacez and partly of small Crustacea (Copepoda), 
from the branchlets of the Alga. With regard to the lower surface 
of the body, I will add here that its outer layer (ectoderm) 
contains numerous nematocysts, which are entirely wanting on 
the buccal tube and all other parts of the body, with the ex- 
ception of the arms. 
Mr. Hincks was unable to confirm Quatrefages’ statements as 
to the structure of the eyes. They appeared to him to be mere 
ageregations of pigment, without any trace of refractive media. 
From my observations, I can only answer for the correctness of 
those statements up to the assumption of a cornea, the existence 
of which I must deny. 
Even if we did not already know from Hincks that Eleutheria 
originates from a Hydroid polype, the demonstration of a gas- 
* T cannot allow it to pass unnoticed that these descriptions are by no 
means in accordance with those of M. de Quatrefages. This naturalist 
states that he observed that a specimen of E. dichotoma, placed on a glass 
plate, always turned up the surface on which the mouth is situated, during 
progression. In accordance herewith, this surface is regarded as the upper 
one (or anterior), and the opposite as the lower (or posterior) ne 
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