STKUCTURE OF THE CROP. 
211 
Dr. Wilde, of Leipzig, iu which, p. 139, he gives the most accurate account 
of the crop and proventriculus of the Acridians and other Orthoptera 
which has yet been published. 
The crop of Anabrus is not divided into two parts, and its cuticula 
forms no ridges, but is divided up into distinct fields (Fig. GO), each of 
which corresponds to a single epithelial cell, for in preparations colored 
with logwood, and examined from the surface, a sharply defined, round 
nucleus appears in the middle of each field. Each field has a spine, which 
rises from its posterior part and points backward. These spines are 
more developed than their fellows on the cuticula of the epidermis. The 
close resemblance of the two cuticulse serves to corroborate the view 
that the crop of insects arises in the embryo, as a secondary invagination 
of the ectoderm. 
Proventriculus. — Dr. "Wilde, in the article just mentioned, speaks of 
the li Kaumagen n as the terminal portion of the crop, bat I see no ob- 
jection to considering it entirely distinct and fully equivalent to the pro- 
ventriculus of other insects with which it is homologous, as Wilde has 
already pointed out. Wilde appears to have overlooked the fact that 
it is sharply limited both in front and behind, and in his figure (1. c, 
Plate IX, Fig. 2) the front limit is not marked. 
An examination of the proventriculus opened, and spread out so as 
to expose the inner surface, shows that there are six large teeth, which 
present a triangular outline, the base facing frontwards, the apex point- 
ing backwards. The ridges of the crop become zigzag just in front of 
the bases of these teeth close to which they terminate. Between the 
single teeth of the proventriculus there are a few parallel ridges, which 
are not continuous with those of the crop, and which terminate abruptly 
with rounded ends, at the level of the apices of the large teeth, that is 
to say at the entrance to the stomach. In the apical portions of the 
large teeth there is more or less pigment, while in the basal portions 
there is almost none. The base of the large teeth is notched ; the apex 
rounded off; and their surface covered with a multitude of minute con- 
ical spines, which project up from the cuticula. 
In Anabrus the proventriculus is fully developed, and resembles that 
of other crickets. 2 * It consists, as in Gryllus domesticus, of two parts : 
one, anterior, serves -as the communication between the crop and the 
proventriculus proper. This anterior part has no definite limit either 
in front or behind. Both parts are traversed by six rows of teeth, but, 
though the rows are continuous, the form of the teeth differs in the two 
parts. If a single row be examined it will be seen that the change from 
one form of tooth to the other is gradual, not abrupt. A transverse 
section through the posterior part of the proventriculus shows the dis- 
position of the parts to be as drawn in Fig. 58. Externally is the muscu- 
lar coat, consisting mainly of circular fibres, intermingled with trachea?. 
I have not succeeded in detecting any longitudinal fibres in transverse 
Wilde, I. c. Arch. f. Naturgesch., 1877, 1. Bd.,pp. 159-165. 
