ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 



953 



the deeper and shallower areolas in this case is similar to that which 

 has been described in Navicula prcetexta, &c., and when they are 

 covered by the lace-like veil of the finely dotted film we have the 

 beautiful and changeable eifect which has proved so puzzling to 

 observers. In whole valves of Reliopelta the larger areolae will often 

 be found showing in the central part of the shell where the fine 

 dotting of the upper film does not extend over them, and their 

 character may there be pretty satisfactorily determined, even if the 

 separated laminae are not detected." 



After referring to the similarity of structure in Halionyx, and 

 dealing briefly with a few other forms, Dr. Cox concludes with the 

 summary of his results which will be found supra, p. 853. 



Fig. 145. 



MICEOSCOPY. 

 a. Instruments, Accessories, &c. 



Japanese Microscope. — Fig. 145 shows a modern Microscope made 

 in Japan and purchased last 

 year in Tokio. The Japanese 

 workman must have evidently 

 had before him one of the old 

 forms of " conical " Microscope 

 which were current in this 

 country in the last century. 



A special feature of the 

 Microscope is its exceptional 

 instability, the feet being made 

 of thin and very springy pieces 

 of metal, so that the whole in- 

 strument vibrates in every part 

 at the least movement of the 

 table. The four objects are 

 inserted in a metal plate which 

 slides from right to left in 

 grooves in the stage. There 

 is no provision, however, for 

 shifting the plate from back 

 to front, and so obtaining a 

 view of difierent parts of an 

 object in that direction. The 

 body tube has 2 eye-piece 

 lenses, and a single-lens ob- 

 jective of about 1/2 in. focal 

 length. The metal of which the 

 instrument is made is copper, 

 coated with a black japan, the 

 body tube being covered with 

 leather figured in gilt. The 

 plate immediately below the mirror can be rotated on the box beneath, 



Scr. 2.— Vol. IV. 3 R 



