FOLSOM: MOUTH-PARTS OF ANURIDA MARITIMA. 99 
In Anurida, they are visible in Stages 1 and 2 only, as slight thick- 
enings of the germ band, which are often ill defined in outline and 
hardly deserve the name of appendages. In fact, their demonstration 
is largely a matter of technique. I dissected over thirty germ bands 
for this purpose, stained them variously, and mounted them temporarily 
in weak glycerine, without finding more than suggestions of the inter- 
calary appendages. At this point, Miss Claypole most kindly sent me 
some preparations which were a little clearer than any I had made. 
These I imitated by staining with Delafield’s hematoxylin, decolorizing 
with acid alcohol and mounting without pressure in xylol balsam. If 
care is taken in decolorizing, a condition may be obtained in which all 
of the germ band between the antenne and mandibles has lost color 
excepting a rather vague patch on either side, usually not as distinct as 
in Plate 2, Figure 8°, app. pr’md. ‘These patches are so slightly, if at 
all, elevated that they are not distinguishable with certainty in transverse 
or sagittal sections of the germ band. In good preparations, the lateral 
boundary of either appendage is indicated by a curving row of ectoder- 
mal nuclei, and this resemblance to the other paired fundaments is 
further shown in the presence of an imperfectly developed core of meso- 
dermal nuclei (Figure 8*, ms’drm.). 
Wheeler and Claypole have represented the appendages much smaller 
than I have, and appear to have figured the mesodermal core only. In 
none of Miss Claypole’s slides are the appendages outlined as sharply as 
in the preparation from which my Figure 8* was made. In glycerine 
the yolk granules interfere with proper observation, but in balsam this 
disadvantage is removed. 
Although the appendages are extremely rudimentary, the evidence 
they furnish of the presence of an intercalary segment is reinforced by 
the condition of the nervous system, for there is at Stage 5 a small 
neuromere (Plate 4, Figure 28, érv’ceb.), which, from its relation to the 
remaining cephalic neuromeres, must be regarded as belonging to the 
premandibular segment. It ultimately fuses with the deutocerebrum to 
form a part of the supracesophageal ganglion. 
Viallanes first called attention to the tritocerebral segment of insects 
and Crustacea ; he was afterwards supported by Wheeler, who found 
that it bore a pair of appendages in Anurida; thus Wheeler (’93, p. 57, 
Figure VI.) discovered the intercalary appendages in this species, and 
indicated their obscurity by representing them by broken circles. 
Claypole (98, p. 263, Plate XXIII., Figures 40, 47) also observed 
the appendages, but erroneously inferred that they became modified 
