No. 4, January, 1921] GENETICS 253 



suggested that these predictions be tested by actual breeding work. This is al present imp 

 sible since two of t be stocks — frayed and hairy have been losl , and t be bybrids of rugose and 

 glazed are sterile. Certain similar cases are cited which show 1 lmt ( !a i lc\- predict ions would 

 probably be fulfilled without prov ing the hypot.hes is, however; for the results also fit the linear 

 hypothesis. In the one case double cross-overs are aol counted, in the other casetheyare. — 

 //. //. Plough. 



1720. Meves, Friedrich. Eine neue Stiitze fiir die Plastosomentheorie der Vererbung. 

 [A new support for the plastosome theory of heredity.] Anat. Anz. 50: 551-557. 2 fig. April. 



mis. 



1727. Mitscherlich, Eilh. Alfred. Uber kiinstliche Wunderahrenbildung. [The 

 artificial production of abnormal heads of cereals.] Zeitschr. Pflanzenziicht. 7: 101-109. 8 fig. 

 Dec., 1919. — All rye plants grown in water culture under greenhouse conditions produced 

 an abnormality in the first spike to appear. The remaining spikes were normal. One wheat 

 plant behaved similarly. In a favorable year on well manured soil a rye plant was observed 

 with condensation of spikelets on "spindle end" of all spikes. Seed from this plant gave 

 progeny with normal spikes. — Fred Griffee. 



1728. Moore, Carl R. The production of artificial hermaphrodites in mammals. Sci- 

 ence 52: 179-1S2. Aug. 20, 1920. — A preliminary report of the author's successful trans- 

 plantation of heterologous gonads into hemicastrated rats. — H. D. Goodale. 



1729. Mossman, J. P. Hybridization and raising of seedling orchids. Florists' Exch. 49: 

 907, 932. April 17, 1920. — In extended account of personal experience in growing seedling 

 orchids it is stated that Catleya gigas crossed with C. Dowiana results in yellow veins in 

 throat and intensified color of entire flower; with C. aurea, gives veining but not intensified 

 color of sepals and petals. Used with a white flower C. Dowiana always puts a trace of rose 

 color through the hybrid. Catleya aurea has no influence on a white flower, but does impart 

 its veining and some of its rich color to lip of offspring. Author uses C. Dowiana or C. aurea 

 as seed-parent in the belief that the character of the female always predominates. Secondary 

 crosses of Brasso-Catleyas onto Catleya give more color than the primary crosses. Many 

 plants do not survive exhaustion of seed production. — J. Marion Shull. 



1730. Nakahara, Waro. Side-to-side versus end-to-end conjugation of chromosomes 

 in relation to crossing-over. Science 52 : 82-84. July 23, 1920. — The stone-fly, Perla immar- 

 ginata Say, is exceptionally fitted for chromosome studies since it has only five pairs of chromo- 

 somes, each pair structurally differentiated from all others. In the prophase of the first sper- 

 matocyte division, homologous chromosomes are connected to each other telosynaptically in 

 the spireme; later they bend toward each other at the synaptic point and become reunited 

 parasynaptically before metaphase. Contrary to the general belief, telosynapsis does offer 

 an opportunity for interchange between chromosomes (crossing-over) ; interchange occurs at 

 the late thick stage only. End-to-end conjugation simply restricts the stage in which such 

 an opportunity is offered. — Bertram G. Smith. 



1731. Nilsson-Ehle, H. Uber Resistenz gegen Heterodera schachtii bei gewissen Ger- 

 sten-Sorten, ihre Vererbungsweise und Bedeutung fiir die Praxis. [On resistance to Hetero- 

 dera schachtii in certain varieties of barley, its method of inheritance and significance for 

 agricultural practice.] Hereditas 1: 1-34. 4 fig. 1920.— Unlike other kinds of cereals, there 

 is striking difference between different sorts of barley concerning the resistance against 

 attacks of Heterodera schachtii. Some sorts of barley are quite immune. By crossing between 

 an immune sort and a susceptible one, immunity dominates. In F 2 nad F 3 a segregation 

 takes place that at least in some cases seems to be monohybrid. For the barley itself, the 

 attacks of this nematode are rather unimportant. If, however, oats or wheat are cultivated 

 in a field which has been planted before with infested barley, these cereals suffer in a great 

 degree from the increased number of nematodes in the soil. For this reason it is of a great 

 practical importance to use minune kinds of barley, thus reducing the number of these worms. 



