MICROSCOPIC OBJECTS. 59 



Fig. 117. A Wheel- animalcule (Noteus quadricornis) , 

 xlOO. 



This animalcule 1 found in large quantities in a large glass 

 jar that I use for the propagation of various species of minute 

 animal life. The description of the species is as follows : 

 " Carapace suborbicular, depressed., scabrous, areolate, with 

 four spines in front and two behind." This, like the preceding- 

 drawing, has been taken from the living animal. It is still 

 more difficult to mount, being rather smaller, than Squamella 

 oblonga but it is quite possible to make some good mounts 

 if a dozen or more can be put in the same cell. 



They are best mounted in alcohol and water. 



Fig. US. Palate of Limpet (Patella vulgata), x 40. 



The palates of the Mollusca form a large series of beautiful 

 and interesting objects, of which the drawing may be taken 

 as a type. They may be easily examined in the whelk, peri- 

 winkle, snail, slug, the water- snails, such as Limnceus, Pla- 

 norbis, &c. The tongues are long ribbon-like bodies, having 

 on their surface beautiful horny (chitine) teeth, which are 

 placed upon them in various patterns, according to the 

 species. From the examination of the tongue, the family &c. 

 may often be determined. The tongue or palate is generally 

 found coiled up at the back of the head ; but this is not a 

 constant characteristic, as it is often found elsewhere in many 

 of the species. After taking it out, it must be boiled some 

 time in diluted potassa fusa, then well washed in warm water, 

 and dried under pressure ; and if wanted for the polariscope 

 or parabolic reflector, it must be soaked in turpentine and 

 mounted in balsam as usual. The above drawing is made 

 from it as seen under the parabolic reflector. 



