Plate 87. 
VERMES. ENTOZOA. ECHINODERMATA. 
The Jntestina, or worms, which pass their existence as parasites in the bodies of human 
beings and other vertebrate animals, constitute a large and somewhat varied class which 
may be divided into two categories, namely: those with a round body, and those with 
a flat one. 
The Nematodes, or round-bodied worms, are destitute of feet and are not articulated, 
their skin being perfectly smooth and naked. They frequently change their habitat, pass- 
ing from-the flesh of one animal into the intestines of another, or from the earth or the 
water, in which they were generated, into the body of some animal where they attain their 
full development. 
1. The Ascaris Lumbricoides infests the smaller intestines of human beings, some- 
times by hundreds at a time, and is also frequently found in the horse and in pigs and 
cattle, its development taking place before it finds its way into the human body. Authori- 
ties are not agreed as to the mode in which it passes into the body. 
2. The Strongylus Gigas is found in the intestines of several of the mammalia, espe- 
cially the dog. The eggs are developed in moist earth, whence the diminutive worms pass 
into their future habitat. 
3. The Trichina Spiralis is a very small, thread-like worm, which seems originally to 
have been peculiar to the rat. It is found in large numbers in pigs, and passes into the 
human body on the flesh of those animals being partaken of. The trichine which have 
thus found their way into the intestines, do not quit their abode again, but increase and 
multiply, the young brood perforating the coats of the intestine and eating their way into 
the muscular tissue, where they increase considerably in size, rolling themselves together 
in a spiral coil and gradually enveloping themselves in a hard calcareous shell, in which 
form they are innocuous, their presence being apparently quite compatible with the enjoy- 
ment of robust health. 
4, The Trichocephalus Dispar grows to a very great length and selects its habitat in 
the human ccecum. 
5. The Echinorhynchus Gigas infests the intestines of pigs andis distinguished by its 
hooked proboscis. — 
The Platyhelminthes, or flat-bodied worms, embrace a large number of very varied forms, 
extremely divergent in their mode of life and place of abode. The Turbellarii are an aquatic 
genus, and have the body thickly covered with fine hairs, which they keep constantly in 
motion. The Planaria are found both on land and in the water, while the Cestodes in 
habit the intestines of human beings and other mammalia. 
6. The Planaria Aurantica is a beautiful species of marine Planaria, found in the 
Mediterranean. 
7. The Common Tape-worm, Tenia Solium, attains a surprising length, being sometimes 
found as long as 20 feet or more. Its has from 700 to 800 articulations, and its head is 
furnished with a series of hook-like appendages, with which it attaches itself to the human 
intestine in which it lives. Its original habitat is in the pig, and it is only on its passing 
into the human body that it assumes the tape-worm shape. 
8. The Broad Tape-worm, Tenia Lata, only differs from the foregoing in being 
broader and stronger, and without the hooked termination at the head, — 
The Echinodermata constitute a class of radiate marine animals, with a hard, cal- 
careous skin, in most case beset with prickles, and a suctorial foot, which serves the 
double purpose of an organ of locomotion and adhesion. 
The Holothurie, or Sea-cucumbers, have several rows of these suctorial feet. Our 
illustrations present two species, viz: 
9. The Holothuria Tubulosa, which attains a length of 12 inches, and is common in the 
Mediterranean, and 
10. The Holothuria Edulis, a native of the Indian Ocean. 
The Sea-eggs, or Sea-urchins, Echinoidea, have a calcareous shell composed of poly- 
gonal plates, set with prickles. They are very widely distributed and extremely sluggish, 
seldom quitting the depths of the Ocean. 
ll. The Echinus Esculentus is very common in the Mediterranean. In our illustration 
ae ot of the body is denuded of its spines, in order to show the disposition of the plates 
of its shell. 
12. The Echinus Mammillatus is a very beautiful and peculiar variety, with extremely 
long spines. 
