G Arachn. 
ARACHNIDA. 
96.. Targioni-Tozzetti, Ad. Notizie sommarie di due specie di Ceci- 
domei una consociata ad un Phytoptus ad altri A can e ad una Thrips 
in Alcune galle del Nicciola, &c. Bull. Soc. Ent. Ital. 1886, p. 419. 
97. Winkler, Willib. Das Herz der Acarinen nebst vergleichenden 
Bemerkungen iiber das Herz der Phalangiiden und Chernetiden. 
Arb. z. Inst. Wien, vii, pp. 111-118. 
Embryology. 
Locy (63) describes the development of Agelena ncevia. At one end 
of the ventral surface of the embryo appears a thickening, the primitive 
cumulus ; at the opposite extremity is the caudal thickening, and between 
these the ventral plate, which is soon marked by furrows into proto- 
zonites. Six of these are distinguishable, and from their lateral portions 
the appendages bud forth. The two first zonites are formed from the 
cephalic plate. The mesosomatic region bears provisional appendages ; 
the two posterior pairs of which form the spinning mammillae. At the 
base of the chelicerae, the poison-glands are formed from certain spongy 
cells, probably by invagination. The lung-sacs arise as a pair of invagi- 
nations. The caudal-plate gives rise to six metasomatic segments. The 
nerve-ganglia arise at the base of the appendages from thickened ecto- 
derm. The stomadoeum gives rise to the pharynx, oesophagus, and 
stomach ; from the proctodoeum are formed the stercoral pocket and the 
malphigian tubes. The development of the eyes is minutely described. 
Kowalewsky (57) describes, in detail, the formation of the germinal 
layers and the development of the alimentary, nervous, vascular, and 
genital systems of Androdonus ornatus. 
Bruce (14), treating of the embryology of Spiders, describes the con- 
version of two pairs of abdominal appendages into the lung-books by a 
process of involution : prior to the involution, the epithelium of the 
appendages assumes the characters or the epithelium of the lung-books. 
There is a fold in the blastoderm surrounding the cephalic region of the 
Spider-embryo, which corresponds to the amnion of Insects. 
Henking (37) describes elaborately the structure of the ovum in the 
Phalangidea. 
Carriere (21) describes the development of various kinds of eyes. In 
some Scorpions ocelli are present in a rudimentary condition. In 
Chelifer, the eyes are devoid of pigment ; each consists of a chitinous 
lens, beneath which are two layers of cells, one lenticular and one retinal ; 
there are no rods. The irregularity of the appearance of these organs in 
various genera of the Cheliferidce, shows that they are organs that are 
disappearing. The same author, making reference to the observations of 
M. Locy, on the development of the eyes in Agelena ncevia t thinks that 
there is no constriction of the invaginated pouch, as described by that 
author. 
Anatomy. 
Grassi (32) gives a description of the anatomy and histology of 
Kcenenia mirabilis, a form intermediate between the Gigantostraca and 
