.PEDALIONIDA. 138 
chitinous lips, which may be seen constantly advancing and receding in the buccal 
funnel, and apparently selecting the morsels which are allowed to reach the trophi. The 
esophagus is short, and the nearly cylindrical stomach has very thick elastic walls ; in 
a dying specimen I have seen the food expelled, and the walls close in quite upon them- 
selves. The gastric glands are somewhat oval; and I think that I have seen two small 
stalked glandular-looking bodies attached to the cesophagus. The intestine is a broad 
short chamber with thicker walls and coarser cilia than those of the stomach. The two 
ciliated straight processes, on the hind end of the dorsal surface, have also a glandular 
structure and secrete a viscous fluid, by threads of which Pedalion may be found moored 
to alge, or to the floating masses of floccose sediment. 
These processes vary greatly in length in different individuals; they are always very 
‘short in the newly hatched female, and are wanting in the male. It is unusually difficult 
to demonstrate the vascular system, as its parts are so frequently obscured by the 
alimentary canal and the limbs. There are two lateral canals, each commencing in a 
plexus close to an eye and bearing a vibratile tag. Hence the canal runs down toa 
second plexus, halfway down the body, with two vibratile tags ; and, skirting the side, 
finally unites with the cloaca. ‘There is no contractile vesicle. The ovary requires no 
notice. Pedalion carries its extruded egg attached to its posterior extremity till it is 
hatched. Of the large oval female eggs only one at a time is so carried; the small, 
round male eggs are carried in clusters: the eggs of different sexes are never present 
together. The newly hatched female resembles its mother, and passes through no 
change but that of growth. The muscular system is very greatly developed. There 
are at least forty striated muscles arranged in pairs of elevators and depressors, not mere 
repetitions of each other like the muscles of a caterpillar, but very various in shape and 
arrangement, and obviously intended for different duties. Figs. 1d, le, 1f show these 
pairs very carefully drawn and, with the printed explanation facing Pl. XXX., render any 
detailed account superfluous. The nervous ganglion lies closely applied to the dorsal 
side of the buccal funnel, and has above it two eyes, widely apart and close to the surface 
of the corona; one in each of its lobes. They are clear refractive spheres set on plates 
of red pigment. Nerve-threads pass from the ganglion to lateral rocket-headed antenne, 
one on each shoulder; and another nervous thread supplies a similar antenna which 
moves up and down in a protuberance on the dorsal median line (figs. la, 1b) just 
behind the dorsal gap in the ciliary wreath. 
The male (figs. 1h, 14) is the merest caricature of the adult female. The large, 
shapely corona, with its flowing curves has become a ciliated knob; the six limbs, with 
their fan-shaped plumes, have been altered into three little stumps, with a bristle or two 
at the end of each; even the huge ventral limb has vanished, and the whole creature 
has shrunk up to barely one-fifth of the length of the adult female. It swims very dif- 
ferently from its mother; for it spins constantly round its own length, like a joint on a 
spit, while at the same time moying forward. Now and then it jerks its side limbs, and 
it uses them to free itself from its shell. There are two longitudinal muscles for retract- 
ing the head and a pair of red eyes, but I could discover no other internal organs except 
the testis and penis. This latter 1 have seen protruded to a length quite equal to that 
of half the animal. 
Length. Female, corona and body, ;4, inch; from corona to end of ventral limb, 
excluding sete, J; inch: male, ;}, inch. Habitat. Clifton (C.T.H.); Birmingham 
(T.B.); warm water-lily tank in the Duke of Westminster's gardens at Eaton, and 
ponds in the neighbourhood of Chester (Mr. Thos. Shepheard): very rare. 

The only other Rotiferon in this Order is Hexarthra polyptera (Pl. XXX. fig. 2),! which 
was discovered by Dr. Schmarda in some brackish water near E] Kab in Egypt, in March 
1853. He describes the body as a blunt cone with a right and left group of cilia on its 
broad end. The trophi resemble those of Triarthra. The stomach is short and broad ; the 
1 Copied from Dr. Schmarda’s fig. 1, Zur Natwrgesch. Agyptens, Taf. iii. 
