426 Reviews—Fyr. Schmidt's Silurian Leperditic, ete. 
to his Revision of the Hast-Baltic Trilobites. The species treated . 
of are :— 
1. Leperditia grandis, Schrenck, in K. 
2 5 baltica (Hisinger), in I. 
3. fe phaseolus (Hisinger), in K. 
4, se Hichwaldi, Fr. Schmidt, in I. 
5 ee Keyserlingi, Fr. Schm., in G3. 
6 < Hisingeri, Fr. Schm., in G. 
7 oS . var. abbreviata, Fr. Schm., in H. 
Excepting L. grandis, phaseolus, and Keyserlingi, these are illus- 
trated anew in plate i.; and in the descriptions at pp. 8-18, the 
points as to which the author has modified his former views, and 
those in which he differs from Mr. Rupert Jones, are fully discussed. 
At page 18 he redescribes Leperditia marginata (Keyserl.) from 
Petschoraland, and gives some new figures in pl. i. figs. 18-19. 
Leperditia Wilniensis, Fr. Schmidt, from “ Hast Siberia,” is newly 
described and figured, p. 21, pl. i. figs. 20-22; and L. Barbotana, 
Fr. Sch., from the South Ural, is noted from new localities, at p. 
22; L. Moelleri (p. 28, pl. i. f. 23-25) is a new species, and L. 
grandis, var. Uralensis, is also new from the same region (p. 24, 
pl. i. f. 26-28). Further mention of the Ural species is given 
at pp. 87, 88, where also var. laevigata of L.. Moelleri is noted. 
Leperditia Lindstremi (pl. v.a, figs. 17-20), and its variety mutica 
(f. 21, 22), L. Nordenskjoeldi, n.sp. (pl. i. figs. 29-32), and L. 
Waigatschensis (pl. i. figs. 33a, b, c), are described (pp. 25, ete.) as 
occurring plentifully in Upper-Silurian Limestones from Waigatsch 
Island in the Arctic Sea. 
The mode of occurrence of the Eurypterids at Oesel, and the 
history of their discovery and collection, are treated of at pp. 28-31. 
The Hemiaspide, represented by Bunodes lunula, Eichwald, and var. 
Schrenckiu (Nieszk.), B. rugosus, Nieszk., and Pseudcniscus aculeatus 
(Nieszk.), are described and figured at pp. 34-46, pl. i. figs. 834-49, 
and pl. vii. figs. 1-6. In the classification (at pp. 48-46) of the 
allied groups, the Hemiaspids stand as follows :— 
( Paleade, in Walcott’s sense [?]. 
‘| Merostomata, ,, ms 
Trilobite. 
‘ Hemiaspide. 
Lurypteride. 
"| Limulide. 
At pages 46-64 the Eurypteride are discussed, and the detailed 
description of HE. Fischeri, Hichw. (pls. ii. iii. iii.a, figs. 1 14, and 
pl. vi. fig. 7), and E. laticeps (pl. iii.a, fig. 16; pl. vi. fig. 6), are given 
in full; and, further, the important Hurypterid genus Pterygotus, 
with its local species H. Osiliensis, n.sp., is treated at large at pp. 
64-83, pl.iv.; v.; v.a, figs. 1-16; vi. figs. 1-5; and vii. figs. 7-11; 
and some woodcuts. 
Ceratiocaris Noetlingi, n.sp. (p. 84, pl. vi. figs. 8, 9, and pl. vil. 
fig. 12), also from Rootzikiill, and mentioned with good reason as 
being a close ally of C. leptodactylus, M‘Coy, is an interesting 
member of this local group of Upper-Silurian Crustacea. 
