VERMES. 5d 
already exists, or the covering is totally cast off when several new and 
durable integuments may be generated, either speedily within short, or 
leisurely at long intervals. 
Tn the following observations regarding form or appearance, I do 
not aim at any thing more than recognition of the subject from external 
aspect. 
I. GORDIUS. 
Body smooth, round, or flattened, sometimes very long, and casting 
itself in a knot. Mouth a longitudinal slit in the under surface, some- 
what behind the anterior extremity. Sides of the head cleft by a groove. 
This genus, which seems sufficiently definite as, 1. Gordius fragilis ; 
2. Gordius spinifer ; and, 5. Gordius simplex.* 
The chief external characters of the genus, therefore, are a groove 
on each side of the head, and a slit in the under surface for the mouth. 
1.—Gorpivs FRAGILIS.—Plate VI. figs. 1, 2; and VIL. fig. 1. 
Having received the subject of this paragraph in the dusk as a fish 
from its captor, ] was induced at first to consider it as a kind of eel / 
nor would any ordinary spectator have probably thought otherwise. 
In appearance, in colour, and in motion, it bore an intimate resemblance 
to many specimens of the most common species. 
But this creature is one of the rarest, and among the most re- 
markable animals of Scotland ; which, from certain external characters, 
seems intimately allied to the Gordius race. 
It is infinitely the largest of any among the whole vermicular tribes 
with which we are now engaged, that is, those void of obvious articula- 
tions, and prominent external appendages. 
* Lamarck comprehends the genus G‘ordius under a section of the Planarian tribe. 
But the definition proposed by him will not apply to those distinguished here by the generic 
name.—Tom. iii. p. 610. 
