REVIEWS. 127 



objects when properly prepared and mounted on a slide. This 

 lingual ribbon acts in practical use exactly like a very hard and 

 sharp file. It is with the rasping instrument that this limpet 

 slowly bores its way into the solid limestone or granite rock, and 

 that the whelk eats a hole through the nacreous material of the 

 hardest periwinkle's or oyster's shell. The back of the tongue has 

 its edges rolled together into a tube, and is the growing part of 

 the organ, where the new teeth are from time to time developed ; 

 and as fast as the front rows get blunted or broken by use, the 

 tube opens gradually forward, and brings the fresh, sharp teeth 

 from behind into play to replace them. The shape and arrange- 

 ment of the lingual hooks is very characteristic of the different 

 groups of snails. One generic form prevails amongst the mem- 

 bers of the genus Helix, another amongst the Papas, a third in the 

 Clausilias, and a fourth in the true slugs. Doubtless, each varia- 

 tion in this respect has been definitely developed with reference to 

 the peculiar food and habits of the different genera." 



Vol. CCLVI., pp. 28-9. 



The Methods of Microscopical Research ; 



Popular JMicroscopical Studies ; 



Studies in Microscopical Science. 



By Arthur C. Cole, F.R.M.S. 



Since our last notice of the above valuable series, we have 

 received the following : — 



Part 5 of the " Methods " is a continuation of the " Preparation 

 of Tissues," and treats of various methods of injecting tissues; 

 Part 6 of Animal and Vegetable Section-Cutting, with the use of 

 the Microtome ; and Part 7 of Stains and Staining. 



Of the " Popular Studies," No. 3 describes the Human Scalp, 

 and contains a plate of a Vertical Section of Human Scalp, 

 double stained ; No. 4 describes the Ovary of Poppy, with a 

 plate of double-stained transverse section of Ovary of Papaver 

 rhccas (unfertilised) ; Nos. 5 and 6 describe a Grain of Wheat, 

 with plates of, ist, a longitudinal section of a Grain cut through 

 the Embryo, 2nd, a plate explaining the Germination of the Grain, 

 which is to be fully described in the next number. The subjects 

 treated in the " Studies " since our last notice have been — " Epi- 

 theUum,' " The Cell as an Individual," " Cartilage," " Morpho- 

 logy of a Tissue," " Areolar Tissue," and " Tendon," illustrated by 

 plates showing Epithelium (three kinds); Micrasterias denticulata, 



