6 ANDERSSON, COMPARISON OF COTTUS POECILOPUS WITH COTTUS GOBIO. 
Revision of the characters attributed by the various au- 
thors to Cottus poecilopus. 
The branched and the unbranched rays in the pectoral 
and ventral fins. 
In the above-mentioned paper in »Annalen des Wiener 
Museums» HEcKEL recognizes no less than four species of the 
genus Cottus, found in the fresh waters of Europe, distin- 
guished by the different branching of the rays in the ventral 
and pectoral fins. These species are the following: Cottus 
gobio Cuv. & Var., from France, Cottus microstomus HEcK., 
from Austria, both of them with simple rays in the ventrals 
and branched ones in the pectorals, Cottus poecilopus HEcCK., 
with simple rays in both pairs of fins, and, lastly, Cottus af- 
finis HEcK., from Sweden, with branched rays in the ventrals 
and simple in the pectorals. He deduces this last-mentioned 
species from EKSTRÖM's description of C. gobio in »Fiskarne t 
Mörkö skärgård>, K. Vet. Akad. Handl., Stockholm, 1831; and 
it seems as if he had overlooked the diagnosis of C. nl 
made by ARTEDI and LINNEUS, or he ought to have noted 
that the description given by EKstTRÖM does not differ from 
theirs, even as to the branching of the rays in the ventral 
and pectoral fins. GÖNTHER rightly remarks that the name 
given to this fish by LINNZUS ought to have been applied 
rather to the Swedish form and another name given to HEc- 
KEL's OC. gobio, if it be necessary to regard the two as sepa- 
rate species. 
In his later work, »Die Siisswasserfische der Östreich. 
Monarchies, written in conjunction with KNER, HEcKEL still 
maintains these four above-mentioned species, adding also a 
new form, Cottus ferrugineus from northern Italy and Dal- 
matia, which according to him has simple rays in both the 
ventral and pectoral fins. He no longer, however, dwells 
upon the different branching of the rays in the paired fins as 
the most important distinction between the species. Instead 
of this he says that the rays in the pectoral fins of C. gobio 
sometimes appear to be simple and sometimes branched and 
that the branching usually increases with age. In the other 
