136 



THE AMERICAN MONTHLY 



[July, 



an aquarium. The attempt to culti- 

 vate them separately in small glasses 

 failed, as they would not multiply. 

 In this respect our own experience 

 has been more fortunate, for several 

 years ago we succeeded in watching 

 the multiplication of a species that 

 was very abundant in a one-ounce 

 vial, in which was a spray of Ana- 

 charis. The bottle was covered with 

 a watch-glass, and the amoebae multi- 

 plied rapidly and were abundant for 

 months. 



The species principally observed 

 was Pelomyxa villosa Leidy. A 

 number of species are carefully de- 

 scribed, but we can only give the 

 names of the new species in this place, 

 wdiich are named Amoeba priiiia^ 

 secunda, tertia, quarta. qui)ita^ all 

 of which are related to Pelomyxa^ 

 and are thrown together by Prof. 

 Leidy, and Amoeba liicida. A general 

 account of various other amcebae fol- 

 lows : 



The diagnosis of an amoeba must 

 be based upon several features the 

 average size, consistence of the pro- 

 toplasm, and through this the charac- 

 ter of the movements, the kind of in- 

 clusions in the protoplasm, such as 

 vacuoles, granules, crystals, the para- 

 sitic living filaments of fungi, and the 

 constituents of food ; but especially 

 the number, size, and structure of the 

 nuclei. 



The contribution is one of great in- 

 terest for the value of the observa- 

 tions on the peculiarities described as 

 well as for the systematic treatment. 

 o 



Synopsis of Diatoms. — To sub- 

 scribers to the Synopsis of Diatoms 

 we have to announce that the volume 

 of text, containing three supplemen- 

 tary plates, was issued some time ago, 

 and a consignment of a sufficient num- 

 ber to complete all the sets has been 

 received for us at the custom-house 

 in New York, where it has been for 

 a fortnight. Eventually it will reach 

 us, and subscribers will be promptly 

 informed of it. In case we should 

 receive it before the Journal goes 



to press this month, announcement 

 of the price will be made in our ad- 

 vertising columns. 



The price of the complete work 

 has been placed at $58.30. This is 

 much more than our subscribers have 

 paid ; but the edition is nearly ex- 

 hausted and the price has been raised. 



We would say for the benefit of 

 those persons who are interested in 

 diatoms that, on the occasion of a fire 

 in our New York office two years 

 ago, a considerable number of plates 

 of the Synopsis were injured by 

 water, so as to be unfit for sale in the 

 complete sets. These injured plates 

 belong to fascicle VI. We have 

 several sets, almost complete, of the 

 injured plates of this fascicle, which 

 we will send to subscribers to the 

 Journal for fifty cents, and ten cents 

 additional for postage. They will 

 be sent on approval on receipt of the 

 amount. 



Recent Progress in the Im- 

 provement OF THE Microscope. — 

 The article on ' Microscopy ' in Ap- 

 pleton's 'Annual Cyclopedia' for 

 18S4, written by Dr. R. H. Ward, has 

 already been mentioned in these col- 

 umns. We have since received a 

 proof copy from the author, which 

 has been carefully read, with great 

 interest. The author begins with the 

 simple microscope, describing some 

 of its forms, and the difi'erent kinds 

 of supports useful for dissecting and 

 other purposes. He then describes 

 the modern form of stand, and says 

 that there is now a distinctive Ameri- 

 can form of stand, differing from the 

 English model formerly extensively 

 copied in this country, and from the 

 continental model. The American 

 stands ' combine nearly all the sim- 

 plicity and portability of the conti- 

 nental stands with nearly all the effi- 

 ciency and scope of adaptations of 

 the more ambitious English instru- 

 ments.' As types he mentions the 

 ' histological' stand of Mr. Bulloch 

 as a ' very simple and inexpensive 

 form yet efficient for a great variety 



