15 
Chrysodomus Heros. (Mollusca, PL VII.) 
Shell elongate ; spire conical, longer than the mouth ; whorls con¬ 
vex, two or three upper with a strong central keel, rest with irregularly 
placed distant rounder tubercles, the last rounded, not keeled ; throat 
white. 
Var. 1. Whorls as with a strong, central, continuous keel; the last 
slightly nodulose. 
Egg-cases ovate-oblong, erect, on an expanded base, contracted 
beneath ; surface deeply punctated, granular. 
Inhab. Arctic Ocean. 
This shell is very like Chrysodomus despectus , but differs from 
that species in the form and surface of the egg-cases, as well as by 
the greater convexity of the whorls, and the strength and angularity 
of the keel on the upper whorls. 
Like the other species of the genus, the white, opake, outer coat 
of the shell is very much inclined to separate from the inner or cen¬ 
tral coat, which presents, where the outer coat is removed, a smooth 
surface of yellowish or brown colour. 
Dr. Richardson observed several specimens of this shell in the 
sand-hills which edge the coast, some distance from the sea. 
I have named this species Heros, as being finest of the genus, and 
in commemoration of the enterprise and heroic conduct under great 
hardship of its discoverer. 
2. Remarks on the Morphology of the Vertebrate 
Skeleton. By Edward Fry. 
The objects of the present paper are,—1st, the brief statement of 
the probability that there are laws which govern animal form, in ad¬ 
dition to the law of final causes ; and 2nd, the a priori discussion of 
certain propositions about the vertebrate skeleton ; being an attempt 
to illustrate the vertebrate by some invertebrate forms, and thus to 
show their unity of plan. 
Section I. 
The existence of laws governing animal form is rendered probable 
by the discovery of such laws as regards the forms of plants, all 
whose parts may be referred to a leaf as the fundamental archetype, 
as is shown not only by the correspondency in many normal condi¬ 
tions, but also by the transmutations of parts, and the monstrosities 
to which the petals, sepals, stamens, &c. are liable. Though the 
greater simplicity of plants, and the more numerous monstrosities to 
which they are liable by nature or art, render the existence of laws 
of the kind spoken of more readily apparent in them than in animals, 
the nature of the proofs and of the conclusions are alike in both 
cases. 
It may, secondly, be remarked, by way of showing a general pro¬ 
bability for such a scheme, that there exist unities of structure both 
in different animals and in different stages of development of the 
same animal, which are independent, so far as we know, of unity of 
