ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
453 
of each antenna there is a small trilohed organ, which is similar to the 
bilobed organ described by Kingsley in Campodea ; it probably aids in 
the determination of the form of the objects touched by the antenna. 
There are five eyes on each side of the head, and each of these consists 
of a nearly spherical mass of protoplasm containing four nuclei and 
covered externally by the cuticula, which is here smooth, though bearing 
small protuberances elsewhere. Immediately below the protoplasm is 
a dense layer of pigment. The different eyes of each side are entirely 
independent, and lie some little distance apart. No structure resembling 
an ommatidium could be found. 
The post-antennal organ described by Laboulbene is situated between 
the eyes and the base of the antenna, on each side of the head. It is a 
rosette-like structure, and consists of from seven to nine ovoid bodies 
radiating from a centre. At the central end of each is a sort of pedicel 
or stalk joining the ovoid portion to the head. Both parts of the organ 
are filled by a pigmented protoplasm continuous with the hypodermis, 
but no nerve-connection was observed. 
The abdominal vesicle is cleft longitudinally, and the hypodermic 
cells lining the cleft are glandular in appearance and are larger than on 
the outer sides of the vesicle. A small tube, in the formation of which 
both hypodermis and cuticula take part, passes forward in the ventral 
line to a median cleft in the lower lip. From the salivary glands a 
duct, which soon fuses with its fellow, passes forwards, but, instead of 
emptying into the mouth, it joins this ventral tube. 
In Lepisma each eye consists of twelve facets, and each ommatidium 
consists of a large cornea, beneath which are two corneagen cells ; the 
crystalline cone has the form of a concavo-convex lens, and at its sides 
are the four cells of the vitrella. The rhabdomere is pyramidal, and its 
base rests against the internal face of the crystalline cone; the four 
retinulse which surround it are densely pigmented, and their proximal 
ends, which perforate the basement membrane, become optic nerves. 
Lepisma seems to represent the highest grade of differentiation yet 
attained by the Thysanura, while Anurida seems to have undergone a 
differentiation perhaps even greater, but followed by a degradation which 
is probably correlated with a change of habits and food. 
B. Myriopoda. 
Anatomy and Histology of Digestive Tube of Cryptops.* — M. E. G. 
Balbiani gives a detailed account of the general and minute anatomy of 
the digestive tract of this Myriopod. He was led to study it by re- 
marking that the oesophagus, and not the intestine, is the region chiefly 
selected by the parasites which infest it. The author enters into a very 
minute account of the object of his investigation. 
y. Prototracheata. 
Australian Species of Peripatus.j-— Mr. A. Dendy has come to the 
conclusion that only one species of Peripatus — P. leuckarti — has as yet 
been found in Australia. Owing to the very distinct and definite mark- 
* Arch. Zool. Exper. et Gen., viii. (1890) pp. 1-82 (6 pis.), 
t Proc. Roy. Soc. Victoria, 1889 (stc;, pp. 50-62. 
