8 MONOGKAPH OF THE FRESH WATER III. 



yet been sufficiently explored. We may expect many species from the rivulets of 

 the highlands and slopes of mountains, as well as in the valleys ; for Pallas cites 

 a C. gobio, L. in the lake Baikal and the fresh waters of Siberia ; but it is more 

 than probable that this is a distinct species. He describes another under the name 

 of G. minutus, which was sent to him by Merk as coming from the fresh waters 

 which empty into the Ochotsk sea. It resembles so closely G. gobio, described in 

 the Eistoire Naturelle des Poissons, that Cuvier himself says that he dares not sepa- 

 rate it. And yet he does not identify it absolutely with the G. gobio, leaving for 

 it a place apart in making the observation that " its snout is perhaps a little less 

 pointed, and the spines above its nostrils a little larger," without giving his opinion 

 on the value of these differences. The size of the specimens which he has examined 

 measured three inches, and if this be the common size, the species is smaller than 

 the G. gobio of the Seine, and many others. 



There is, in this reserve of Cuvier, not to identify definitively two fishes of such 

 distant countries, and nevertheless so similar to each other; there is, I say, included 

 in this reserve, the whole spirit of modern science, a spirit profoundly philosophical, 

 the spirit of future progress. 



We have deemed it necessary to make several generic divisions of the species 

 hitherto comprised in the genus Cottus. This part of our labor was published in 

 the Proceedings of the Boston Society of Natural History,^ and we think it in place 

 to transcribe here the historical paragraph which relates to that question, since it 

 might be controverted by some one. 



Artedi established the genus Cottus in 1738 with the following characters : gill 

 membrane containing six distinct bony rays ; head larger than the body, depressed 

 and acute. Two dorsal fins ; the anterior composed of flexible spines. Ventral 

 fins small, having only four soft rays. Skin scaleless.^ 



He places in the first rank the fresh water species having tioo spines on the head, 

 of which C. gobio is the type, being the only one known at that time. Next to 

 this, the species with more spines on the head, including not only the salt water 

 species having a smooth skin, but two others, which have since become, one the 

 type of the genus Aspidoplwrus, the other the type of the genus Gallionymibs. 

 Artedi himself went thus beyond the limits of his genus by placing in it the two 

 last species, as their body is covered with scales. 



Linnaeus'' alters Artedi's genus by giving as the only character for it, " a spiny 

 head broader than the body." Linnaeus went farther ; he transposes the species 

 and places at the head G. cataphr actus, the type of the genus Aspidophoi-us, of later 

 date, and which Artedi placed at the end of the genus Cottus. His third species 

 belongs now to the genus BatracJms, and the fourth to the genus Platycephalus : 

 the G. gobio is the last. 



0th. Fabricius'* followed the example of Linnceus. 



But Cuvier* recalls that the primitive type of the genus Cottus was G. gobio 



» Vol. iii., 1850, pp. 183, 303, and vol. iv., 1851, p. 18. " Genera Piscium. 



^ Systema Naturae, ed. xii. ■• Fauna Groenlandica, 1780, p. 159. 



' Histoire Naturelle des Poissons, iv., 1829, pp. 142, 150. 



