370 = =©Reviews—Dr. G. Holm—Hyolithes and Conularia. 
the higher Liémtes region. In the Chasmops beds only a single 
species is definitely known, whilst the three species met with in the 
Trinucleus division belong to the sub-genus Orthotheca. From the 
Upper Silurian only three species were discovered by Lindstrém in 
the Isle of Gotland. 
As regards the relationship of the Swedish forms of Hyolithus to 
those occurring in other countries, there is a considerable resemblance 
to those from North America, and the Lower Cambrian forms from 
that country described by Walcott correspond with those from the 
Middle Cambrian of Sweden. Owing to the imperfect preservation 
of the British species no comparison is practicable. There does not 
appear to be a single species in common with those from the 
Bohemian basin, though these latter are numerous and fairly well- 
preserved, and thus this group tends to confirm the evidence from 
the Trilobites, Gasteropods and Cephalopods that there was no 
direct connection between these areas at the period. 
From a table giving in detail the references to the names, authors, 
and the distribution of the known species in the Cambrian-Silurian 
rocks, it appears that 55 species occur in the Cambrian, 68 in the 
Ordovician, and 22 in the Silurian series; and if to these are added 
04 species from the Devonian, Carboniferous, and Permian rocks, 
the total number of species of this group reaches 178. 
In the family Conulariidz only the single genus Conularia, Miller, 
is recognised. The earliest known species is from the summit of the 
Cambrian in North America. The genus reaches its culmination in 
the Ordovician and continues apparently as far as the Lias. In 
Sweden there are 12 species from the Ordovician, 5 from the 
Silurian, and one common to both. Only one of these, C. cancellaia, 
is common to the Bohemian basin and this species is widely distri- 
buted over the Continent of Europe, and probably is identical with 
C. niagarensis, Hall, from the Silurian of N. America. 
As a rule the shell in these fossils is well-preserved, with the 
finest details of ornamentation, and the author has attempted a 
division of the genus into four groups, based on the surface sculp- 
turing and the character of the segmental lines. In the first group, 
Leves, the shell exhibits only transverse wrinkles formed by the 
lines of growth, and the segmental line is depressed. In the second, 
Longitudinales, there are raised longitudinal ribs and the segmental 
line is elevated; in the third, or Monilifere, there are transverse 
ridges or rows of tubercles; whilst in the fourth, or Caneellate, the 
transverse main ridges are interrupted, and finer longitudinal ridges 
are likewise present. 
The specific descriptions are accompanied by carefully drawn 
figures, showing the fossils and their surface characters enlarged, 
which thus greatly facilitate comparison with other forms. For the 
convenience of those to whom Swedish is unknown, the author has 
appended a short summary in English, giving a synopsis of the 
different species. 
