4.64. CLASS ECHINODERMATA. 
LioRHYNCUS, Rud., 
Which have the mouth in the form ofa small proboscis. 
LINGUATULA, PENTASTOMA, Rud., 
Have the body depressed and trenchant on the sides; and 
the transverse wrinkles are marked by strong and numerous 
crenulations. The skin is thin and weak; the head is broad 
and flatted; the mouth pierced underneath ; and at each of 
its sides are two small longitudinal clefts, from which issue 
little hooks. The intestine is straight; the genital vessels 
long and contorted. Both have their issue at the posterior 
extremity. Near the mouth are two cceeca, as in echinorhyn- 
cus. A white filament surrounds the mouth, and gives out 
two descending trunks, in which I think I have recognized 
some appearance of a nervous system. 
This genus connects the intestina cavitaria, with the pa- 
renchymata. 
One is known. Tenia lanceolé, Chabert. Polystoma teni- 
oides. Rud. Hist. ii. xii. 8—12.; Pentastoma tenioides, id. 
Syn. 123, which attains to nearly six inches in length. It 
remains in the frontal sinuses of the dog and the horse. 
It is here that we should place 
PRIONODERMA, Rud., 
Whose body and intestines are very similar; but the mouth 
is at the anterior extremity; simple, and armed with two 
small hooks. 
But one is known, which attacks the silurus. Cucullanus 
ascarotdes, Goetz. pl. viii. f. 2, 3. Rud. Hist. xii. 
I think that we should place at the end of the intestina of 
this order, but as a family sufficiently different, and which 
should be divided into several genera, when their economy 
shall be better understood, 
