* 
This difficulty was overcome by Barrois? b se of ce 
_ tion, a little expedient may be recommended which the 
_Teagent. After the long narcosis in poor water, the pol 
given the most uniformly good results. In this way the! 
398 - The American Naturalist, 
egg was in many cases pricked with a very sharp need before. 
into Seales alcohol. It is necessary to do this undera 
the only satisfactory one. In Pallene the larger size of the egg1 
a study of the earlier stages much easier, but the other gente 
much simpler development. 
Method of Rendering Opaque Nemertean Eggs 
parent.—The eggs of Nemerteans which have a direct deve 
are opaque, and cannot be rendered aap cle ro 
glycerine. The m xture must be allowed to fice: gradually th 
causes a Three mixtures, containing glycerine in ine 
proportions were used, the first consisting of one part glycerine 
parts water ; the second, equal parts of glycerine and water 
three parts of glycerine to one of water. Enough carmine aad 
to give the mixture a wine color. Each mixture was allowed 
to kill Hydroids, Actiniz, and similar forms in an expan 
tried in many places and on many forms, and has uniformly 
of value. The animals to be killed are left i ina small aa 
effect of i e ites: This manifests itself in one or 
some forms draw themselves completely together, while ¢ y 
half expanded and limp in the water. They are t 
colonies or in large groups into fresh salt water which is at the 
time cool, The effect of a mass of cool, pure water is such as ti 
the animals to expand fully and promptly. Immediately 
sion is seen to reach its maximum, in. the course 
seconds, they are transferred by a quick motion to some 
lack energy enough to contract forcibly, as is usually the € 
ing reagents, alcoholic corrosive sublimate and picro- 5 
* Recherches sur l'embryologie des Némertes, Lille., 1877, P- 191- 
