ENTOZOA. 



13 



last joint of the upper gradually lengthens and bccouies two 

 joints. The then lowermost joint in the same manner becomes 

 elongated, and divides into two; and by a repetition of tho 

 same process the animal, in a short « 



time, regains its original length. 

 In Ascaris lumbricoides, the most 

 common intestinal parasite of the 

 human body. Dr. E Sebright had 

 estimated the number of ova, which 

 one mature female contained, at 

 64,000,000. When creatures of 

 structure and habits so sinc^ular 

 were first found in the bodies of 

 birds, fishes, quadrupeds, and other 

 animals, it was naturally a subject 

 of wonder how they got there, and 

 some naturalists imagined that 

 tliey were produced by the tis- 

 sues of the animal body — in fact, 

 by equivocal generation. When, 

 however, it was discovered how 

 elaborate was their construction, 

 and that each animal contained 

 millions of fertile ova, the truth of 

 this theory was disproved, and the 

 naturalist was taught to attribute 

 their production, through the re- 

 gular laws of generation, to Him 

 who created the highest as well 

 as the lowest order of beings. 



If we turn to any works in which 

 the Entozoa are figured, it is im- 

 possible not to be struck with their 

 great diversity, and with the ela- 

 borate delicacy of some of the organs with which they are 

 furnished. Such examination, even when not followed up by 

 that aid which the microscope affords, will convince the most 

 unthinking of the accuracy of the following very beautiful 

 passagefrom Professor Owen's "Lectures on the Invertebrate 

 Animals:" — "In creatures surrounded by, and havmg every 

 part of their absorbent surface in contact with, the secreted 

 and vitalised juices of higher animals, one might have antici- 



Pig. 6 — Tapewobu. 



