THE SHADS, THE EELS, AND THE LAMPREYS 299 
naturalists as to the specific rank of the grig, or broad-nosed 
eel—an animal of precisely similar habits, so far as they are 
known, and of very similar appearance to the common eel. 
It has a broader head and blunter nose than the other ; but 
the feature which seemed to Dr. Gunther to justify its 
recognition as a separate species is the dorsal fin, which 
“begins further backwards, the distance between the com- 
mencement of the dorsal and anal fins being shorter than the 
head.” It has a very wide range, being described in the 
British Museum Catalogue as inhabiting European waters 
generally, the Nile, China, New Zealand, and the West 
Indies. 
Third Sub-class: CYCLOSTOMATA: SUCKER-MOUTHED 
FISHES 
The British list of fresh-water fishes is brought to a close 
by two species of the peculiar and archaic type Cyclostomata, 
creatures whereof the skeleton is entirely cartilaginous. The 
vertebral column is represented only by the notochord, or 
undivided dorsal chord; there are no ribs, no limbs, no 
scales, and no real jaws, the mouth being suctorial, surrounded 
by a circular or nearly circular lip. There is but one nostril ; 
the reproductive organs are single, consisting of but one 
ovary or milt in each fish; and on each side are seven 
branchial openings to the gills. 
First Family: PETROMYZONTIDA: THE LAMPREYS 
But for the presence of two rayed dorsal fins and a small 
rounded caudal fin, the lampreys, both in appearance and 
parasitical habits, are far more suggestive of large worms than 
fishes. The skin is naked, and the body shaped like that of 
an eel or worm. The mouth is suctorial, circular when open, 
and forms, when closed, a longitudinal furrow ; not transverse, 
