The Microscope. 43 



Figure 22. Ch. lovicatus, oral aperture with projecting oral 



cilia. 



Figui-e 23. Ch. spinifer, sp. nov. ; posterior ventral region. 



Fio-ui-e 24. Ch. spinifer, oesophagus showing brace-shaped 

 thickenings. 



Figures 25 and 26. Eggs of Ch. spinifer. 



Figure 27. Spines and scales of Ch. spinifer. 



Figure 28. Ch. acanthodes, sp. nov. ; posterior dorsal aspect. 



Figure 29. Ch. acanthocles, appearance of spines and double 

 scales. 



Figure 30. Ch. acanthodes, posterior ventral aspect. 



Figure 31. Ch. rhomboides, sp. nov. ; a caudal branch. 



Figure 32. Ch. rhomboides, appearance of rhombic scales. 



Figui-e 33. Ch. rhomboides, probable arrangement of the scales. 



Figure 34. Ch. rhomboides, shape of the scales. 



Figure 35. Ch. rhomboides, ventral aspect of the head. 



USES OF CELLOIDIN. 



BY T. B. BEDDING, A. M., PH. D., F. K. M. S. 



I HAVE been using celloidin, for embedding purposes, for two 

 years past, and find it the best of anything I have ever used for 

 preparing ovaries, fetuses, insects and dehcate objects, such as hairs, 

 glands, etc. of plants, where it is desired to make sections of these 

 and retain every part in situ. I usually mount the sections with- 

 out removing the celloidin. 



The celloidin is prepared by dissolving in equal parts of 

 sulphuric ether and absolute alcohol to the desired consistency, and 

 is kept in very closely stoppered bottles. The object is prepared by 

 dehydrating in absolute alcohol, taking the necessary preliminary 

 steps to prevent shrinkage and change of structure. 



When the object is throughly dehydrated it may be placed in a 

 solution of the celloidin, at once, or, what is better, allow it to 

 remain a few hours or days, according to the nature of the object, 

 in a mixture of two parts absolute alcohol to three parts of ether; 

 then place in the solution of celloidin. First, place in rather a 

 thin solution, and after the object has remained in this till 

 throughly saturated, remove it to a thicker solution. If necessary, 

 make such openings and incisions on the object as will allow the 

 celloidin solution to penetrate all parts. Leave the object in the 

 solution until thoroughly saturated. I have objects that have been 

 in the celloidin for over two years, and have never had any 

 iniurv result from remaining in it so long. 



