37 
SILURIAN FOSSILS OF RUSSIA. 
Russia, the Orthoceratites duplex is as common as in the tracts of which we are now 
treating ; whilst the Russian Orthoceratites vaginatus is represented in Sweden by 
the closely allied O. trochlearis. The Lituites convolvans, it may be further stated, 
is common to these two countries. 
The lower limestone of Russia abounds in Trilobites, two of the prevailing 
species being, as in Norway and Sweden, the Asaphus expansus and Illcenus crassi- 
cauda ; the former being the most abundant in Russia, the latter in Scandinavia. 
Referring to the work of Pander, in which some of the species are published, we 
may further state, that the characteristic Russian crustaceans, including the Caly- 
mene Fischeri (Eichw.j, C, polytoma (Dalm.), Ampyx nasutus and Metopias aries 
(Eichw.), are Scandinavian forms, two of which have been described by Dalman, 
and the last mentioned by Boeck. Of these, the Asaphus expansus being the most 
profusely distributed in Russia, though as yet very rare indeed, if known at all in 
the British Isles or France, we here annex a figure of the usual form of the species (4) 
of the following woodcut, adding in a note its description by Dalman 1 . This species 
Asaphus cornutus, var, of A, expansus ? 
Asaphus expansits. 
1 The following is Dalman’s description of Asaphus expansus : “ Capite semilunari, angulis posticis 
rotundatis ,• sulco subbasali transverso profundoaue ; linea faciali (postice) oblique extrorsum decurrente, 
tandem intus flexa ; pygidio semi-orbiculari, costis obsoletis. (Syn. Entomostracites expansus, Wahl., 
and Asaphus cornigerus, Brongn.).” According to Dalman, this species has many varieties, and his figure, 
pi. iii. fig. 3 ( c ), exhibits one with prominent eyes, but not approaching to the remarkable varieties (1) 
and (3) of our woodcut. Ueber die Palceaden oder die so genannten Trilobiten von J. W. Dalman, p. 45. 
