BY HENRY TRYON. 81 
to the appendages of Tracheata is only owing to their being 
endowed with terminal segments—and even these joints are but 
little differentiated, the extreme claw-bearing portion alone having 
any large amount of independence. On the other hand, as 
pointed out by Moseley, the fact that the first pair of appendages 
are terminated by modified claws, cause these appendages to be re- 
garded as foot-jaws, and Peripatus therefore as being related to the 
Arthropods. ‘The slime-secreting glands which are connected with 
appertures at the tips of the second pair of appendages are com- 
parable only with organs which exist in tracheates. ‘The muscular 
system, Owing to its being constituted of separate bundles and to 
its non-striated character, is that of a member of the Vermes. 
Again, the nervous system is quite that of an animal lower than 
the Arthropods. ‘Two cerebral ganglia united above the esophagus 
surround the mouth and give off two non-ganglioniated nerve-cords, 
which pass almost to the extremity of the body, with only faint 
indications of commisures. In the circulation system we find 
the simplest conditions as compared with other tracheates, there 
is a “dorsal vessel” or heart as in insects, but it extends the whole 
length of the body as in Myrapods. The alimentary canal, too, 
is of simple form, as in Myriapods and in the larva of insects, and 
the peri-enteric space or celom is devoid of those dissepiments 
which exist in the Annulata in connection with the metamerism of 
their bodies. Again, the respiratory system, with its generally 
distributed tracheze, which Moseley was the first to observe, points 
to Peripatus as being an immediate ancestor of the air-breathing 
Anthropods. 
A review of the literature which might be grouped under the 
heading Peripatus would teach of whaf immense interest is this 
animal to students of biology. Savants, too, have combined their 
scientific acumen in elucidating the lessons to be taught by an 
examination of this animal. And this interest is further em- 
phasised by the fact that the Government Grant Committee of the 
Royal Society granted, in 1883, Ar1oo to enable Prof. Sedgwick 
to proceed to the Cape for the purpose of studying Peripatus, 
and the Lords of the Treasury moreover agreed, it is believed, that 
one whole volume of the memoirs relating to the scientific work 
of the Challenger Expedition should be devoted to Peripatus. 
Its discovery then in Queensland—its rediscovery in Australia— 
is therefore a noteworthy event. Like our Ceratodus it was no 
doubt formerly—but in an earlier geological epoch than it— 
widely distributed. It is, however, an animal which might have 
F 
