1865.] Entozoa. 147 



enough to the young naturalist, but hardly entozoa. These are the 

 Anguilluliche. Who that has examined a drop of dirty water under the 

 microscope, has not been puzzled with the appearance of a number of 

 twisting, twirling, eel-like bodies, which no author on the microscope 

 condescends to describe ? To this family Dr. Cobbold refers vinegar- 

 eels and paste-eels, and says, very truly, of them, their " intimate 

 organization and course of developement is not yet well understood." 

 Why does not J some fancy microscopist take these small fish under his 

 especial care, and let the world have the result of his labours ? They 

 would be very interesting. 



Nest to these small eels come the hair-worms, the Gordiidas. 

 In this family the tendency of the ova to develop themselves in the 

 body of living animals is seen. It is more or less the characteristic 

 of the whole of the entozoa to travel, and take up their abode in 

 various localities, now inside and now away from a living animal. 

 In this group of animals fragmentary observations have been made, 

 which seem to show that great variety takes place in the method of 

 their wandering. The Oxyuridaa or true thread-worms, are the next 

 family. They are represented by a species Oxyuris vermicular is, only 

 too well known as an occupant of the human body. The fact of their 

 " wandering " has not been well made out, though suspected by 

 Kuchenmeister and others. They are easily distinguished by their 

 minute size from the next family, the FilaridaB, which include the 

 whip-worm (Trichocephalns dispar), and the round-worm (Ascaris 

 lurribricoides), so commonly found in the human intestines. Members 

 of this family are found very generally in the intestines of the higher 

 animals. They gradually pass into the family Strongylidce. One of 

 the best known forms of this group is Sclerostoma Synganus, a worm 

 which attacks birds, and which is known to infest poultry, producing 

 a disease familiarly known as the " gapes/' It has been found in the 

 trachea of the turkey, domestic fowl, pheasant, partridge, stork, magpie, 

 common woodpecker, starling, and swift. It would be found in other 

 birds, probably, were it looked for. Other forms of this family have 

 been found to infest the common porpoise and the narwhal. These 

 creatures have been carefully dissected and studied by Mr. Busk, and 

 two plates of their structure, from his pencil, illustrate the text. 



The last two orders belonging to Dr. Cobbold's new sub-class 

 Anenterelmintha, are the Acanthocephala and Cestoda. The first of 

 these orders, called also from their peculiar structure thorn-headed 

 worms, are found infesting almost all classes of vertebrate animals, 

 but up to the present time none have been discovered in the human 

 body. They are. especially abundant in birds and fishes, and are 

 found anchoring themselves in the mucous membranes of the intes- 

 tines of these animals, by means of the retractile thorns, or proboscis, 

 which they bear on their heads. Upwards of one hundred species of 

 these worms have been described. The one which Dr. Cobbold has 

 chosen as the type for his descriptions is the Echinorliyncus anthuris of 

 Dujardin, a little worm a quarter of an inch in length, found in the 

 intestines of the lesser water-newt (Lissotriton punctatus). The de- 

 velopment of these animals has been recently observed by Leuchart 



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