192 



The Ratio betiveen Spindle Lengths in the Spermatocyte Meta- 

 phases of Helix pomatia. 

 By C. F. U. Meek, M.Sc, F.L.S., F.Z.S. 



(Communicated by Sir W. T. Thiselton Dyer, K.C.M.G., CLE., F.R.S. Received 

 July 15, — Read December 4, 1913.) 



[Plate 12.] 



Introduction. 



I have recently shown that in Forficula uuricularia the length of the 

 mitotic spindle, i.e. the distance between the centrosomes, seems to be 

 a constant at the conclusion of each spermatocyte metaphase. The ratio 

 between the lengths found at this stage is almost identical with the ratio 

 between the radii of two spheres of which the volume of one is equal to 

 twice that of the other ; and, since the volume of the primary spermatocyte 

 cell in the metaphase is presumably equal to twice that of the secondary 

 spermatocyte, connection is suggested between the length of the spindle and 

 the volume of the cell. 



I now propose to measure spindle lengths in the spermatocyte metaphases 

 of Helix pomatia. As in the case of Forficula, the chromosomes are spheres 

 or very short rods, and all seem to divide on the spindle at the same time ; 

 the conclusion of each metaphase is therefore easily recognised. If the 

 lengths are found to be constants, and if the ratio between them is 

 approximately 1*26:1, the connection between spindle length and cell 

 volume is again suggested : if, on the other hand, lengths are not constants, 

 or if the ratio between them is not approximately that mentioned above, the 

 suggested connection is at once disproved. 



Material and Methods. 



The material, which consisted of the hermaphrodite gland, was obtained at 

 the end of May, and was preserved in Flemming's strong chromo-aeeto-osmic 

 acid fluid and the platino-aceto-osmic acid fluid of Hermann. The material 

 remained in the fixative for 12 hours, and, after being washed thoroughly in 

 running watef and passed through successive strengths of alcohol, was 

 embedded in paraffin. Sections were cut 8 /x thick with an ordinary 

 Cambridge rocking microtome. 



The stains vised were Heidenhain's iron hematoxylin and iron brazilin,* 

 * Hickson, S. J., 'Quart. Journ. Micro. Sci.,' 1901, vol. 44. 



