1882.] 



MICKOSCOPICAL JOUKNAL. 



55 



cules and in their arrangement, but 

 it is uncertain Avhether these will re- 

 quire new generic names, or if they 

 should be included in Carter's genera. 

 An American form allied to Mey- 

 enia, Carter, has led Mr. Potts to es- 

 tablish the genus Heteromeyenia, in 

 which the shafts of the birotulate 

 spicules are not uniform in length. 

 Another new genus, Carterella, has 

 been made, to include a form describ- 

 ed by Mr. Potts last year, before the 

 Academy, as Spongilla tentasperma, 

 and mentioned on page i6, of Vol. II 

 of this Journal. The distinguishing 

 peculiarity of this genus, that the 

 tube surrounding the foramen of the 

 statosphere is elongated, and divides 

 into 2-5 long tendrils by which it re- 

 mains attached to stems or roots dur- 

 ing the winter, reminds us that prob- 

 ably it was a form of this genus that 

 we found in the Lehigh River, near 

 Bethlehem, last summer, during a few 

 days sojourn with Mr. Wolle. The 

 elongated, branching tube puzzled us 

 at the time, but it seems clear enough 

 now that the form we observed 

 was Carterella tenosperma. Another 

 species, C. tubsiperma, having a still 

 longer tube, was discovered by Prof. 

 Kellicott and Mr. Henry Mills, of 

 Buffalo. A third species, C. latitenta, 

 with long, broad, flat and ribband- 

 like tendrils, has been found by Mr. 

 Potts, which h« states to be the most 

 conspicuous and peculiar of our 

 American forms. 



Mounting. — It seems to us quite 

 an unfortunate circumstance that 

 many of our most able investigators 

 with the microscope regard mounting 

 as a difficult and troublesome opera- 

 tion. It is seldom that any of them 

 deny the value for future reference, 

 of the preparations they make, and fre- 

 quently we hear them express regrets 

 that they cannot refer to some speci- 

 men that has not been preserved, 

 either to verify a previous observa- 

 tion or to supplement it by further 

 examination. While we do not ad- 

 vise that specimens should be preser- 



ved without regard to their intrinsic 

 value — a course too often followed 

 by amateurs, which eventually results 

 in a grand cleaning up of slides of 

 worthless preparations — there can be 

 no doubt that in the course of regu- 

 lar work many specimens are found 

 which show different points of struc- 

 ture far better than these can be 

 demonstrated a second time by days 

 of labor. In this article we have es- 

 pecially in mind those busy, profes- 

 sional men who value every moment 

 of their time, and who, not having 

 learned any simple process for mount- 

 ing, are discouraged from attempting 

 it by the multiplicity of processes and 

 cements given in the books. To them 

 we wish to say, that with a turn-table, 

 only two cements, a bottle of Canada 

 balsam, a few needles mounted in 

 wooden handles, some slides and cov- 

 ers, and a few simple articles that are 

 sure to be at hand, any specimen 

 whatever can be mounted in five 

 minutes, or at least so preserved on a 

 slide that the finishing touches may 

 be added at any convenient time. 



For almost every specimen that re- 

 quires to be mounted in a fluid, such 

 as glycerin, water or other preserva- 

 tive, the only cement necessary is a 

 simple solution of shellac in alcohol. 

 The proper method of using this has 

 already been described in this Jour- 

 nal (Vol. I, p. 149). 



It has stood the test of long use, 

 and the practical operations of mount- 

 ing are expeditious, and exceedingly 

 simple to carry out. Shellac cement 

 is one of the best and most reliable 

 cements known; it hardens rapidly, 

 and it is even practicable to prepare 

 a cell of considerable depth, and to 

 use it for mounting within an hour. 

 The use of shellac alone, however, is 

 liable to the objection that it becomes 

 brittle, and the cover-glass is then 

 easily detached if the slide is drop- 

 ped. To prevent such a mishap, the 

 slide should be finished with a mix- 

 ture of equal parts of asphalt and 

 gold size. 



Instead of cementing the cover- 



