PAIJENCHYMATA. 509 



T. lata, Rud. (The Common Tape-worm. ) The joints are broad, short, 

 and furnished with a double pore in the middle of each side. It is very 

 frequently twenty feet in length, and it has been found upwards of a hun- 

 dred. The large ones are nearly an inch wide, but the head and anterior 

 portion of tlie body are always very slender. This species is exti-emely 

 injurious and tenacious. The most violent remedies frequently fail to expel 

 it In Man. 



T. solium, L. Ver solitaire of the French. Its joints, the anterior ones 

 excepted, are longer than they are wide, and have the pore 'placed alter- 

 nately on one of their edges. It is usually from four to ten feet in length, 

 but much larger ones are sometimes met with. The vulgar idea that but 

 one of these animals is found at a time in the same individual is very far 

 from being true. Its detached joints are styled cucurbitini. It is one of 

 the most dangerous of the intestinal worms and the most difficult to expel. 



From these ordinary Tjenias, on account of the form of their head, 

 are distinguished various others, forming the Tricuspidaria, &c. 



Naturalists have also distinguished from the ordinary Tasnae those 

 which, with a similar head, that is one with four suckers, have the 

 body terminated posteriorly by a bladder. Their joints are not as 

 distinctly marked as in the preceding ones. The genus 



Cysticeecus, Rud. 



Vulgarly termed Hydatids, is composed of those in' which the bladder sup- 

 ports but a single body and one head. They are particularly developed in 

 the membranes and cellulosity of animals. 



C. cellulosse. This species is the most celebrated of the whole number, 

 and lives between the fibres of the muscles of the Hog, producing the dis- 

 ease called measles. It is small, and multiplies prodigiously in this disgust- 

 ing disease, penetrating into the heart, eyes, &c. Similar animals have, it 

 appears, been observed in certain Monkeys, and even in Man. 



FAMILY IV. 



CESTOIDEA. 



The fourth family comprises those which are destitute of external 

 suckers. 



But one genus is known. 



LiGULA, 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 ion- 



