375 



Gastrochaena und Clavagella zu Aspergillum. Ebenso wenig erscheint 

 danach Da 11 's ^ Eintheilung der Bivalven in die drei Ordnungen: 

 Anomalodesmacea, Prionodesmacea und Teleodesmacea, 

 als den verwandtschaftlichen Beziehungen der in diesen Ordnungen 

 vereinten Formen entsprechend. So umfaßt die Ordnung der Ano- 

 malodesmacea folgende Unterordnungen : Solenomyacea, Anatinacea, 

 Myacea, Ensiphonacea, Adesmacea; die Ordnung der Prionodesmacea 

 die: Nuculacea, Arcacea, Naiadacea, Trigoniacea, Mytilacea, Pecti- 

 nacea, Anomiacea, Ostreacea ; die Ordnung der Teleodesmacea die : 

 Tellinacea, Solenacea, Mactracea, Carditacea, Cardiacea, Chamacea, 

 Tridacnacea, Leptonacea?, Lucinacea, Isocardiacea?, Veneracea. 

 Wien, Juli 1892. 



2. A Method for Making Paraffine Sections from Preparations stained 

 with Ehrlich's Methylenblue. 



By G. H. Parker, Cambridge, Mass., U. S. A. 



eingeg. 27. Juli 1892. 



In the course of some studies on the ganglion in the optic stalk 

 of the crayfish , the writer found it necessary to devise a method for 

 making paraffine sections from preparations in which the nervous 

 elements had been stained with Ehrlich's methylenblue. The follow- 

 ing preliminary account, prepared at the suggestion of Herr Geheim- 

 rathF. E. Schulze, gives the essential steps in the method which 

 was finally adopted. 



In order to stain the elements in the nervous system of a crayfish, 

 Vio to Y20 ccm of a 0,2 % aqueous solution of methylenblue was in- 

 jected into the ventral blood sinus, the animal afterwards being kept 

 alive in a glass aquarium. 



In about 15 hours many of the ganglion cells and nerve fibres in 

 the peripheral as well as the central nervous organs were stained in- 

 tensely blue. 



Preparations made in this way, after being removed from the ani- 

 mal , retain their color only about an hour, but as is well known they 

 can be made more nearly permanent by treating them with reagents 

 which precipitate the methylenblue, such as picric acid, ammonium 

 picrate, potassic iodide, potassic ferro-cyanide , chromic acid or corro- 

 sive sublimate. Of these reagents the one last named, in addition to 

 being an excellent fixing reagent, yielded the most satisfactory preci- 



■? Dall, On the Hinge of Pelecypods and its Development , with an attempt 

 toward a better subdivision of the group. American Journ. of Science, vol.38. 1889. 

 p. 460. 



23* 



