1883.] 



MICROSCOPICAL JOURNAL. 



189 



upper ring, having been cut with a 

 gun-wad punch, has a bevel on the in- 

 side, and being set with the smaller 

 hole uppermost, the bevel helps to 

 hold the brass ring in place. This 

 plan has many advantages, — the ob- 

 ject may be examined uncovered, 

 there is no trouble from running in, 

 etc. 



D. S. Kellicott gave an account of 

 several species of vorticellidae found 

 upon the cray-fish. Two species were 

 described as new, viz. : Cothurnia 

 variabilis and Epistylis NiagarcB. The 

 former is peculiar to the gill-cavities, 

 and is often so abundant that its hab- 

 itat is colored brown, and possibly they 

 cause asphyxia in the host. A notable 

 peculiarity of the species is the fact 

 that chains of loricte are often found, 

 which appear to result from increase 

 by division, the "'new" animal com- 

 pelled to leave the shell in which it 

 was separated fastens to the outside 

 of it and gets one of its own ; this 

 may be repeated indefinitely, — six 

 in a chain is not uncommon. The 

 Epystilis appears to be nearer to 

 E. balanceian than to any other species. 

 In other short papers the same writer 

 described Cothurnia lata found on a 

 a species of Diaptimus, and gave an 

 account of two internal parasites of 

 the cray-fish. 



Mr. W. H. Walmsley presented a 

 paper on Photo-Micrography, giving 

 the results of his own researches and 

 those of others, to date, in this im- 

 portant branch. 



Dr. A. M. Bleile and Adolph Friel 

 jointly presented a paper on the 

 Effects of Division of the Vagi on the 

 Muscles of the Heart. The same 

 investigators presented last year a 

 paper having for its object the demon- 

 stration of nutritive or trophic nerves 

 for the heart. By request of the so- 

 ciety they continued their studies and 

 reported the results. This time ex- 

 periments w^ere mainly upon pigeons ; 

 some of their conclusions are as fol- 

 lows : The fibres of the pigeon are 

 more delicate and more friable than in 

 the rabbit ; in young pigeons the cross- 



striation of the muscular fibres of the 

 heart is indicated by the fine granules 

 which might be mistaken for begin- 

 ning degeneration, after the division 

 of the one vagus, only there follows in 

 the heart muscle of the pigeon a 

 finely fatty degeneration about equally 

 marked on both sides ; after double 

 vagotomy the degeneration is more 

 marked. 



Dr. Thad. S. Up de Graff read a 

 paper on certain worms. He described 

 a new rotifer Brachionus Gkasonii. 

 One peculiarity is the possession of a 

 dorsal horn or spine. " The lorica is 

 in form an oblong square with two 

 transverse angles posteriorly, acutely 

 truncate in the dorsal aspect. From 

 the four acute angles thus formed, pro- 

 ject with a slight inward curve, four 

 spines of nearly equal length and at- 

 tenuated at the free extremities. The 

 anterior margin of the shell is spine- 

 less." The length of the lorica, in- 

 dependent of the spines is 1-145 inch : 

 found in stagnant water. 



Dr. Christopher Johnson exhibited 

 some new polarizing crystals, a de- 

 scription of which may be published 

 in the American Monthly Micro- 

 scopical Journal. 



Rev. Francis Wolle's short paper 

 on Fresh-water Algae was read, also 

 one by Mr. J. Kruttschnitt, on Ferns 

 and their Development. 



A paper which called forth consid- 

 erable discussion, much of which was 

 friendly, was read by Dr. Geo. E. 

 Blackham, On the Relations of Aper- 

 ture to Amplification in the Selection 

 of a Series of Microscopic Objectives. 

 The author's reasoning we cannot 

 condense ; his conclusions are as 

 follows : " I have selected as a set of 

 powers sufficient for all the work of 

 any microscopist : 



One 4-inch objective of .10 n. a. = 

 12° angle, nearly. 



One i-inch objective of .26 n. a. = 

 30° angle, nearl3^ 



One ^-inch objective of .94 n. a.= 

 140° angle, nearly. 



One ^-inch objective of 1.42 n. a. 



The first two to be dry-working ob- 



