No. 416.] THE TEXAN KG@NENIA. 621 
sacs as lung books, they must represent those organs in an 
extremely simple form, in a form, moreover, which strongly sug- 
gests their origin from invaginated appendages serially homol- 
ogous with those of the cephalic and thoracic segments." 
The two anterior sensory organs do not appear different in 
any respect from the same organs of K. mirabilis. The lateral 
organs, howevet, though situated in about the same place, 
consist of three sensory rods each, instead of the two blades. 
These are short-pointed rods pressed close siti 
together and projecting, when at rest, for- 
wards and outward. Fig. 4 is a camera 
drawing of these lateral sensory hairs, under 
a high magnification. In cross-section the 
hairs appear as three rings in contact with Fıs. 4 — Lateral sense 
one another. I am unable to make out on me 
the surface of these organs anything more than the minute 
projections which are found over the entire surface of the 
animal's body. 
The second and third joints of the chelicere, which form 
pinchers, in specimens examined for this special purpose, were 
found to be each provided with eight teeth. The teeth of the 
fixed portion are long and very acute, with barbs at the base ; 
while the teeth of the movable joint are short, broad, and blunt. 
The above are the most evident differences of the two species 
of Kcenenia, unless it be that there are more segments in the 
caudal flagellum of one than of the other. I have examined a 
number of complete specimens of both males and females, and 
find in every case that the tail is made up of fifteen segments. 
Grassi states for his species, which has been redescribed for all 
other points except this, that it possesses thirteen or fourteen 
joints. 
Internal Anatomy. 
In considering the internal anatomy of this minute animal, 
several difficulties have arisen which I fear I have not entirely 
surmounted. The extreme minuteness of the cells of the very 
delicate tissue enclosed in the comparatively heavy chitinous 
case makes microscopic study rather unsatisfactory. 
