2 Verm. 
YEHMES. 
The Trichoscolices are intimately connected with the Annelida on the 
one hand, and on the other with the Physemaria and lower Hydrozoa. 
The water-vascular system, and the qomplication of the reproductive 
organs, indeed, afford clear marks of distinction. MalacoMella appears 
to unite the Hirudinea with the Turhellaria and Trematoda ; Polygordius 
appears to be transitional between the Turhellaria and the Polychceta ; 
while the Rotifer a^ in many respects, represent larval forms cff the Poly- 
chceta and Gephyrea. 
The Nematoscolices contain the Nematoidea, “ which are as remarkable 
for the universal absence of cilia as the Trichoscolices are for their pre- 
sence ; and which are further so clearly distinguished by the arrange- 
ment of their nervous and muscular systems, and of their water- vessels, 
and by their ecdysis.” With these are placed the Nemaiorrhyncha. 
The Chcvtognatha are regarded as an independent division. 
The Acanthocephala (and Cestoidea) are, it is suggested, modifications 
of the Mesozoic type. 
Of the six series into which the animal kingdom is arranged, the 
second (Annuloid) contains the Trichoscolices and the Annelida ; the 
third (Arthrozoic), the Nematoidea and” Arthrojpoda (and ? the Chceto- 
gnathd ) ; the fourth (Malacozoic), the Rotifera^ with the Polyzoa and 
Mollusca] the fifth (Pharyngopneustal), i\iQ Enteropneusta dmdi Tunicata. 
The Vermes are thus classified by VoN Hayek (1) : — 
A. No ciliated circlet of tentacles, or dermal lobes at the anterior end of 
the body.' 
I. Body not segmented, or the segmentation not extending beyond 
the dermo-muscular tube. 
a. Body flat 1. Platyhelminthes, 
/3. Body rounded. 
i. Body divisible into head, trunk, 
and tail . . . .3. Chcciognatha. 
ii. No division of the body into head, 
trunk, and tail. 
I. No blood-vascular system . 2. Nematohelmmthes. 
II. A blood- vascular system . . 4. Gephyrea. 
II. Body segmented, and the segmentation ex- 
tending to the internal organs . 5. Annelides. 
B. A ciliated circlet of tentacles, or ciliated dermal 
lobes at the anterior end of the body . 6. Ciliata. 
The class Platyhelminthes are thus arranged in orders - 
A. No enteric canal 1. Cestoides, 
B. An enteric canal. 
i. Parasitic ; surface of body not ciliated 2. Trematodes. 
ii. Free-living; surface of body ciliated . ^/Turhellaria. 
The Cestoides are divided into seven families : 1, Tieniidce ; 2, Bothrio- 
cephalidui] 3, Ligulidoi-, 4, Tetrarrhynchidcc] 6, Tetraphyllidece] 6, Diphyl- 
lidece ; 7, Caryophyllideoe. 
The Trematodes are arranged in six families : 1, Monostomidea ; 2, 
