PARENCHYMATA. 373 
FAMILY IV. 
CESTOIDEA. 
The fourth family comprises those which are destitute of 
external suckers. | 
But one genus is known. 
t 
Liauna, Bloch. 
Of all the Entozoa, these appear to be the most simply organized. 
Their body resembles a long riband; it is flat, obtuse before, marked 
with a longitudinal stria, and finely striated transversely. No ex- 
ternal organ whatever is perceptible, and internally we find nothing 
but the ova, variously distributed in the length of the parenchyma. 
They inhabit the abdomen of certain Birds, and particularly of 
various fresh-water Fishes, enveloping and constricting their intes- 
tines to such a degree as to destroy them. At certain periods they 
even perforate the parietes of their abdomen to leave it. One of 
-them, : 
q L. abdominalis, Gm.; L. cingulum, Rud.; Getz., XVI, 4—6, 
inhabits the Bream(1). In some parts of Italy these worms are 
considered agreeable food. 
(1) For the others, see Rud., Hist., I, p. IL, p. 12,/and Syn., 132. 
N.B. In the intestines of Seals, and of Birds that prey on Fishes, we find Worms 
very similar to the Ligule, but with genital organs, and even a head analogous to 
that of the Bothryocephali. M. Rudolphi supposes that these Worms of Birds are. 
the same as the Ligule of Fishes, which can only acquire their full development 
after they have passed from the abdomen of the latter into the intestines of the 
former. 
