208 THE ESSEX NATURALIST
According to Tate Regan1 and other authorities, the four-spined variant
of the species is quite common, the two-spined is on the other hand a rarity ;
whilst it may perhaps be suspected that it is more often overlooked than rare,
it is clearly much less common than the four-spined type. The specimen
referred to by Tate Regan was from Newark.
The present specimen is 2.2 cm. long and it is clear, from the relative
proportions and from the existence of a hardened subcutaneous patch on the
back in front of the first existing spine, that it is the normally anterior spine
which is missing ; the integument is quite unmutilated along the entire dorsal
region. A minute spine-like epidermal tubercle lies between the existing
spines proper ; but this is even smaller than the rear spine, lies left of the
median line and lacks any trace of elevating apparatus or posterior fin-web
or hardened subcutaneous basal area ; actual examination leaves no grounds
for supposing that this has any connection with the missing spine. If it is
indeed to be regarded as a rudiment, then it is of a supernumerary spine and
presents us with the unlikely occurrence of a three-spined specimen of the
four-spined variant!
The two-spined variant is not recorded for Essex in Laver's Memoir.2
REFERENCES:
1. Tate Regan : The Freshwater Fishes of the British Isles, London, 1911.
2. Laver : The Mammals, Reptiles and Fishes of Essex, London, 1898.
(Essex Field Club Special Memoirs III). W. B. Broughton.
Diagnostic Characters of the Spined Loach (Cobitis taenia L.)—During the
Roding trip (already referred to in the note on the Two-spined Stickleback)
of the S.W. Essex Students' Field Club, a number of loach were also taken
which the writer, using MacMahon1 and being himself no ichthyologist,
provisionally (and rashly, as it turns out) identified as the Spined species
Cobitis taenia L., hitherto unrecorded for Essex as for many other counties,
though considered by MacMahon to be probably not so much rare as es-
caping notice.
Let it be quickly said that there appears to be nothing wrong with the
diagnostics as given by MacMahon, but a small elevated process before the
eye was taken for the bifid spine referred to by him. On more detailed
examination it turned out to be the elongated tubular anterior external
nostril, standing up in front of the socket-like posterior nostril. Reference
to Yarrell2 leads to the conclusion that this is present in both the British
loaches, and that the bifid spine of the Spined Loach is additional to it.
Fin-ray counts categorically and regrettably define the Roding specimens
(using Yarrell's diagnostics) as the Common Loach (Cobitis barbatula L.).
The Spined Loach therefore remains still as it was in Laver's3 day "apparently
naturally absent from . . . Essex rivers" (with the possible exception of the
Essex watershed of the Cam). The hope that MacMahon may be right in
his belief that the species will yet be recorded from many more than its present
charted localities leads to the publication of this note which may help others
not to fall into the same error as the writer.
REFERENCES:
1. MacMahon : Fishlore ; London, Pelican Books, 1946.
2. Yarrell : History of British Fishes, 3rd Edition, Vol. I ; London, 1859.
3. Laver: The Mammals, Reptiles and Fishes of Essex; London, 1898.
(Essex Field Club Special Memoirs III). W. B. Broughton,