and Laboratory Methods. 1^^" 



mounted in glycerin or balsam. For histological study the larvae may be killed 

 in Flemming's fluid ; after one hour's exposure they should be halved and again 

 placed in the fluid for another hour, and then thoroughly washed in running 

 water in a washing bottle for twenty-four hours. Perenyi's fluid for six hours 

 also fixes the tissues very well ; after three hours in the fluid the larvae should 

 be halved. Larvae for entire mounts should be prepared as follows : Select 

 transparent specimens and keep them in clear water for a day or two, until the 

 alimentary canal is emptied. Then place the larva in a mixture of absolute 

 alcohol (9 parts) and ether (1 part), holding it in the desired position with small 

 sable brushes until it is set (three to ten minutes). After several hours' exposure 

 to this fluid transfer to absolute alcohol so as to remove all the ether. Pass 

 through oil of cloves to new benzine balsam. Many points in the anatomy may 

 be elucidated by fresh specimens teased out in two per cent, caustic potash, or 

 by those killed in the fluids above mentioned, and stained in carmin or haema- 

 toxylin before teasing out. In staining in toto with carmin or Delafield's haema- 

 toxylin it is necessary to permit the stains to act for at least a week. Material 

 prepared by the methods above described may be successfully sectioned in either 

 paraffin or celloidin. Serial sections in the paraffin are facilitated by coating 

 the block with soft paraffin. 



The peculiar nuclear structures of the salivary glands may be studied in 

 material fixed in a fluid composed of equal parts of one per cent, osmic and 

 acetic acids allowed to act for several minutes. The glands are then stained in 

 acetized methyl green followed by carmin, and are mounted in glycerin. The 

 glands are easily secured from decapitated larvae, passing out with the blood, or 

 being readily released by gentle pressure. 



The eggs of Chironotniis are very favorable objects for the study of insect 

 development ; they are abundant, quite transparent, and the larval stage is 

 reached in the brief period of six days. The authors recommend hot, thirty 

 per cent, alcohol half saturated with corrosive sublimate for killing the egg-chain 

 for subsequent sectioning and staining by the Heidenhain method. c. a. k. 



Guiart, J. Les Mollusques Tectibranches. This is a resume of the author's mono- 

 Causeries Scientifiques de la Soc. Zool. de graph of these mollusks, and is devoted 



S iJ, S; 7,;o''' " ■"■ ''•" '' "''■ principally to the Bum./, and the 



Aplysidce. A very complete outline is 

 given of the gross anatomy of several types, and a modified classification is 

 proposed for the group. The PleurobranchidcE are included with the Nudi- 

 branchs, and the group, as a whole, are derived through some such form as 

 Adeon from the Prosobranchs by a process of detorsion as shown in the com- 

 parative study of the nervous system. The author recommends the subcutaneous 

 injection of one cubic centimeter of five or ten per cent, hydrochlorate of 

 cocaine to overcome the extreme contractility of Aplysia. Muscular relaxation 

 is thus secured in several minutes. Tissues may be fixed by injection of sub- 

 limate-acetic by way of the gill. This paper is one of an excellent series of 

 lectures by specialists before the Zoological Society of France. c. a. k. 



