2 Arachn. 
ARACHNIDA. 
of Insects, and the ancestors of the present Insecta and Arachnida must 
have diverged from a common stem of IVacheata at a time when the 
second pair of maxillae (equivalent to the first pair of legs in Arachnids) 
were still organs of locomotion. The order of development of append- 
ages and segments is very different in different ordinal groups, showing 
that the order of appearance is a matter of embryonic convenience, and 
not very significant morphologically. The formation of the layers and 
the embryonic envelopes in the Tracheata (in respect to which there is a 
striking constancy thronghout the group) is treated, of, pp. 377-379. 
The authors principally followed and quoted are : Metschnikoff, Rathke, 
Stecker, Balbiani, Balfour, Barrois, Claparede, Herold, Ludwig, and 
P. van Beneden. 
Bertkau, P. Verzeichniss der bisher bei Bonn beobachteten Spinnen. 
Verb. Ver. Rheiul. xxxvii. pp. 215-343, pi. vi. 
315 species of Araneidea, belonging to various families, and distributed 
among 106 genera, are recorded. Fam. Theraphosidee (^Atypidee, auct.), 
1 gen. 2 spp. Dysderidm^ 3 gen. 5 spp. Salticidce (Attidce^ auct.), 
12 gen. 26 spp. lliomisidce {Thomisidm et Sparassidoi^ auct.), 13 gen. 
42 spp. Drassidoi (Drassidee et Anyphamidee, auct.), 16 gen. 73 spp. 
Lycosidoi (includes Oxyopideti), 8 gen. 31 spp. Agelenidcn {Agelenidu'., 
Argyronetidee, et Ilahnudoiy auett.), 9 gen.’ 16 sp. Dictynidee {Dictynidca 
et A maurohiidcey Siuct.), 4 gen. 11 spp. Ulohoridcey 2 gen. 2 spp. Ere- 
sidee, 1 gen. 1 sp. Scytodidee, 2 gen. 2 spj). Theridiidce {Micryphantidccy 
TheridiidcCy et Pachygnathidee, auct.), 28 gen. 68 spp. EpeiridcBy 8 gen. 
35 spp. Five species (belonging to PhilodromuSy Drassus, PhrurolithuSy 
Trocliosay and Lophomma [^Walchenaera, Bl., pt.]), are described as new. 
. Verzeichniss der von Prof. Ed. van Beneden auf seiner im Auf- 
trage der Belgischen Regierung unternommen wissenschaftlichen 
Reise nach Brasilien uud La Plata im Jahren 1872-73 gesammelten 
Arachniden. M(^m. cour. Ac. Belg. 4to, xliii. pp. 1-120, pis. i. 
& ii.. 
Contains a record and description of 3 species of Scorpionidea (1 new), 
58 species of Araneidea (2 gen. and 36 spp. new), 14 of Phalangidea 
(^Opiliones, auct. ,: 2 gen. and 6 spp. new), and 4 spp. of Acaridea. 
Cambridge, 0. P. On some new and little known Spiders of the genus 
Argyrodes. P. Z. S. 1880, pp. 320-342, pis. xxviii.-xxx. 
Describes 27 species, of which 21 are new. 
Croneberg, a. Ueber die Mundtheile der Arachniden. Arch. f. Nat. 
xlvi. pp. 285-300, pis. xiv.-xvi. 
An important paper on the mouth-parts of the Arachnida, comparing 
in detail those of the various Orders of that Class. 
Karsch, F. Arachnologische Blatter (i.). Z. ges. Naturw. liii. pp. 
373-409, pi. xii. 
This paper is divided into 10 sections, and treats of numerous species 
and genera (some new) of various Orders and Families of Arachnida, 
from many different parts of the world. 
