262 GENETICS [BoT. Absts., Vol. X, 



3717, HoxDA, H. Spermatogenesis of aphids; the fate of the smaller secondary sper- 

 matocyte. Biol. Bull. 40: 349-368. 4 pl- 1921. — In Stomaphis yanois the diploid nxmiber of 

 chromosomes is 10. The 1st spermatocyte division results in unequal cells. Eight chromo- 

 somes divide and are distributed equally to secondary spermatocytes, while 2 lag and then 

 go undivided to a larger cell. The larger cell divides equally and forms 2 functional sperma- 

 tozoa. The smaller secondary spermatocyte divides equally, the 2 small cells elongate, 

 become active, and move toward sustentacular cells, but do not become attached; unable to 

 obtain nourishment, they degenerate, their length being reduced and the cytoplasm increasing 

 around the nucleus. In Neothomasia populicola and Macrosiphum ambrosia the smaller 

 secondary spermatocyte divides, but spermatids do not develop. — A. Franklin Shull. 



1718. HovASSE, R, L'activation parthenogenetique des oeufs de grenouille rousse (Rana 

 temporaria L.) dans les milieux hjrpotoniques et hypertoniques. [Parthenogenetic activation 

 of the eggs of Rana temporaria L. in hypotonic and hypertonic solutions.] Compt. Rend. Acad. 

 Sci. Paris 172: 1137-1139. 1921. — The author placed unfertilized frog eggs, from the uterus, 

 in water to allow the jelly to swell, then removed the jelly and returned the eggs to distilled 

 or tap water (distilled water is much more effective than tap water). The eggs swell, shrink, 

 and swell again until the 1st cleavage appears. In unfertilized eggs, from the uterus, placed 

 in various solutions, — e.g., LiCl, NaCl, KCl, various sugars, urea, — and transferred after 

 2-3 hours to tap water, segmentation occurred in 6-7 hours. Removal of the jelly is favorable. 

 Best results are secured with hypotonic salts, and with iso- or hypertonic non-electrolytes. 

 Osmotic pressure does not offer a complete explanation, as imbibition by cell colloids is also 

 involved. — C. L. Parmenter. 



1719. Hutchison, C. B. Heritable characters of maize. VII. Shrunken endosperm. 

 Jour. Heredity 12: 76-83. Fig. 20-24. 1921. — Plants from kernels with shrunken endosperm, 

 occurring in maize from the Ponka Indians in Nebraska, bred true for this character, which 

 was shown to be inherited as a simple recessive to the normal endosperm and is designated 

 by the genetic symbol sh. F2 of crosses between normal and sh deviated but slightly from 

 the 3:1 relation and in back-crosses but slightly from 1 : 1, indicating that shrunken endosperm 

 is differentiated from the normal by the single factor pair Sh sh. Selling an Fj plant of the 

 cross between a homozygous red-aleurone shrunken plant of the genetic constitution C C 

 sh sh with a colorless-aleurone non-shrunken plant, cc Sh Sh, produced an ear with both shrunk- 

 en and non-shrunken as well as colored and colorless kernels, but with all shrunken kernels 

 colored. This indicated that the Sh sh and Cc factor pairs are linked. — Progenies from back- 

 crosses between Fi plants and the double recessive suggest that the factor pair Sh sh belongs 

 to the same linkage group as Cc and Wx ivx. Several Fi plants of the cross non-shrunken 

 waxy {Sh Sh wx wx) X shrunken starchy {sh sh Wx V/x) back-crossed to double recessive 

 shrunken waxy plants produced kernels as follows: Non-shrunken starchy 229, non-shrunken 

 waxy 813, shrunken starchy 833, shrunken waxy 230. — The very close approximation of the 

 Sh sh — Cc linkage relation by that of Sh sh — /{ suggests that Cc and It are very closely linked, 

 or are on opposite sides of Sh sh and approximately equally distant, or are allelolorphic. 

 H.M. Steece. 



1720. Kanda, M. Field and laboratory studies of Verbena. Bot. Gaz. 69: 54-71. 4 pl; 

 26 fig. 1920. — Several intermediate types were found between the 3 established species, 

 V. angustifolia, V. stricta, and V. hastata. Cytological studies on these 3 and on an inter- 

 mediate between the last 2 showed 4 haploid chromosomes in V. angustifolia, 6 in the others. 

 Some of the developmental characters of the intermediate types resemble V. stricta, some 

 V. hastata, and some are intermediate. Chromosome behavior is normal and similar in all 

 three. — Merle C. Coulter, 



1721. Krieq, Hans. Uber die Bildung von Streifenzeichnungen bei Saugetieren. [On 

 the formation of the striped coat pattern in mammals.] Anat. Anzeiger 54: 33-40. 6 fig. 1921. 

 — Three types of striping of mammalian coat patterns are recognized: (1) Zebra-tiger-hyena 

 pattern with vertical stripes over the body, circular stripes at the extremities, and stripes 



