1898.] MICROSCOPICAL JOTJKNAL. 71 



show the numerous blood-vessels passing to the lateral 

 brancliisB from the main trunk along the intestine. The 

 color of the blood may remain unchanged for years. 



EOLis. — The beautiful Nudibranchs quickly lose color 

 in alcohol. Hence transfer them after a short stay in 

 dilute alcohol and arrange on the glass to dry. A strong 

 solution of gum is then placed over it and the whole 

 kept damp with dilute alcohol to enable the gum to sat- 

 urate the specimen and protect the pigment from the 

 balsam in which it is soluble. A bluish tint may dis- 

 appear at once but the other color remains permanently. 



Spider crabs. — These may be kept transparent with 

 their growth of sertularians, sponges and ascidians. 

 Being arranged on the glass, gentle and then stronger 

 pressure is applied, using waxed paper and flannel- 

 covered glass, till the whole is pressed flat without dis- 

 tortion except a slight widening of the body and legs. 

 The leg muscles show welL 



MoLLUSCA. — Various species show their general 

 anatomy if we first dissolve away the shell with hydro- 

 chloric acid in dilute alcohol. The organic matter of 

 the shell retains a natural form and shows the attach- 

 ment of the various parts which may be stained or not as 

 preferred. The membranous residue with its form and 

 color left after dissolving away the carbonate of lime 

 makes nice slides. 



Medusa. — Dissolve out all the salt. Keep the specimen 

 in methylic alcohol diluted with half its bulk of fresh 

 water, for some hours. Shake to prevent adhesion to 

 the vessel. Then digest repeatedly with fresh dilute 

 alcohol. Specimens are so colorless and transparent as 

 to show little of their structure but if kept many months 

 in alcohol they turn brown-yellow and show structure 

 quite well. But a far better way is to stain them with 

 tincture of madder, Beale's carmine, methylene-blue, 

 port-wine or tincture of galls. Beale's carmine stains 



