BY GERARD KREFFT, ESQ., F.L.S 207 



I had jotted down and sketched, what I considered at least 

 thirty species, and these in a great measure owing to the ova- 

 test, were reduced to fifteen or sixteen. My practical acquaint- 

 ance with Entozoa is of a recent date, but I find the subject of 

 such interest that every moment which could be spared from 

 other duties has been devoted to it. There is no necessity to 

 point out the importance of the study of this group of animals 

 to the well being of millions, but as many people consider it 

 a particularly nasty subject, I will try and prove to them that 

 it is not so. 



The fresh intestines are put into a flat dish, and a stream of 

 water is kept running over them till quite clean, a rough board 

 beneath prevents the escape of any of the smaller Entozoa which 

 the water may force out. The parts are then opened and 

 after a gentle flow of the element for several hours, the worms 

 may be picked out with a camel hair brush. 



Not having time to make the usual preparations for the 

 microscope, and being generally well supplied with duplicate 

 specimens, I spread some out on glass slides, and observed them, 

 making the necessary sketches at the same time ; they dried gra- 

 dually and the changes which the difi'erent parts underwent were 

 carefully noticed. Whenever I wish to refer to a specimen it is 

 put under the microscope, and any part, even if it is a cestoid of 

 several feet in length, can be examined without difficulty. To 

 clear up doubtful points, some wet preparations are necessary, 

 and these are kept in glass tubes to be used when the first 

 plan fails. 



When once dry, the objects are transparent, and under the 

 glass look most charming — the fact is, few persons unacquainted 

 with them will believe what they are. Some retain their colour, 

 and are therefore still more valuable. 



I have mounted the largest flukes in the same way, but had 

 to keep them for a day or so in water and press them slightly 

 when they were too thick. With a view of giving some idea of 

 the arrangement of the Entozoa, I have added Professor von 

 Siebold's system, and I need not observe that his first order of 

 Gystici is now generally accepted as part of the Cestoidea ; the 

 genera arranged under that head being no doubt young tape- 

 worms. 



