Miscellaneous. Ill 



of which about '6<i have been found for the tirst time by me. The 

 total number of animals of the Caspian at present known must 

 be more than 150. If this fauna is poor in comparison with those 

 of other seas, such as -the Mediterranean and even the Black Sea, my 

 researches prove that it is much richer than it has hitherto appeared ; 

 and the assertion of Von Baer, that " whoever chooses to be led away 

 by his mihnswMS to establish new species must elevate slight varieties 

 to the rank of species," unfortunately* appears not to be justified. 

 This is especially evident if we consider that this sea has even now 

 been but little examined, particularly in its deepest parts, where 

 animal life seems to be manifested most intensely. The water of the 

 Caspian being poor in saline constituents, it is in the deep parts that 

 its composition most nearly approaches that of sea- water. 



T intend giving you only the most general results of my researches 

 as they appear at present before the study of the animals collected 

 has been terminated, and even, I may say, at the moment wiien I • 

 am commencing it. 



In its fauna the Caspian presents the characters of a great half- 

 salt lake which possesses its own peculiar species of animals, and , 

 also contains others which occur in other seas. The former {e. g. 

 the new Gohius and Benthophili) originate from living or already 

 extinct species, or they result from slight raodilications of allied 

 species living in other seas, as is the case with Goregonus leuciclithys, 

 Calictis caspia, Eichw. (which is a good species), PetromyzonW agneri, 

 Kessl., Ti atinnus mitra, sp. n., and Ileniera Jlava, sp. n. The other 

 animals (that is to say, those which occur also iii other seas) possess 

 a great tenacity of life, since they still prosper where their less robust 

 ancient colleagues have long since died out : in this category we 

 place llotaUa veneta, Sahellides octocirrata, Lagancida repens, Mysls 

 relicfa, and Idotliea entornon. 



These species common to different seas show the affinities of the 

 Caspian Sea to the Aral Lake, the Black Sea, and the Arctic Ocean ; 

 but the affinities with the glacial sea seem to be more recent than 

 those with the Black Sea ; for in the latter certain species, such as 

 the seals, Goregonus leucichfJigs, and others which are common to 

 the Caspian and giacifil seas, are wanting. We may suppose that 

 in the Tertiary epoch there existed in Europe and in the neighbour- 

 ing parts of Asia a vast closed basin of fresh water. By an upheaval 

 of the crust of the earth, due to the action of the volcanic forces which 

 still make themselves felt energetically in the region of the Caspian, 

 thii was separated into some smaller basins, which are the existing 

 Black Sea and the Aralo-Caspian basin. The latter in its turn was 

 afterwards divided into two, just as we still see smaU salt lakes 

 separate from the Caspian. At the same time the water of the 

 glacial sea penetrated into the basin of the Caspian, which stiU had a 

 slight connexion with the Black Sea, so that only a small number of 

 animals could arrive thei'e from the glacial sea. Hence we find 



* I say " unfortunately, ' because I do not like new species, and ret 

 find myself compelled to establish a considerable number. 



