142 GENETICS [Box. Absts., Vol. VII, 



933. Salmon, E. S. On forms of the hop (Humulus lupulus L., and H. americanus Nutt.) 

 resistant to mildew (Sphaerotheca humuli (D. C.) Burr.). IV. Ann. Appl. Biol. 6: 293-310. 

 1920. — In continuation of studies previously published the author now reports three groups of 

 hop plants immune or resistant to hop mildew (-S. humuli). Group 1 comprises several forms 

 of a variety having yellowish-green leaves and known as the "Golden Hop." A female 

 form is immune and a male form is susceptible to the attacks of mildew both when grown in a 

 greenhouse and in the open. Another female form of this type is slightly susceptible to this 

 fungus in the greenhouse only. — Group 2 comprises individual seedlings of the wild hop (H. 

 lupulus) raised from seed obtained from Vittorio, Italy. Certain individuals proved to be 

 immune, others highly susceptible to mildew. It is stated that the seedlings which are 

 immune when grown in the greenhouse may, when grown in the open, show susceptibility, 

 which as a rule is slight. The conclusion is drawn that different seedlings have distinctive 

 physiological or constitutional characters, which are constant under the same environment 

 and confer immunity or susceptibility upon the respective seedlings.— Group 3 comprises a 

 male form of H. americanus which is immune to mildrew when grown in a greenhouse. Under 

 the same conditions several American cultivated varieties proved susceptible.— TT^ W. 

 Stockberger. 



934. Skupienski, F.-X. Sur la sexualite chez les Champignons Myxomycetes. [On 

 sexuality in the Myxomycetes.] Compt. Rend. Acad. Sci. 167: 31. July, 1918. 



935. Slocum, Rob R. Selection and care of poultry breeding stock. Bur. Anim. Ind., 

 Farmers Bull. 1116. 10 p., 6 fig. 1920.— Practical suggestions concerning management of a 

 breeding stock. — William A. Lippincott. 



936. Slonaker, James R. Some morphological changes for adaptation in the mole. 

 Jour. Morphol. 34:335-372. 4 pi. 1920.— In adaptation to fossorial habits, the sternum, 

 pectoral girdle and fore-limbs of the American mole, Scalops aquaticus, have been greatly 

 enlarged and modified, thus increasing the size of the anterior part of the body. To allow the 

 enlarged anterior part of the body to pass the posterior part when the animal turns in its 

 burrow, the pelvic girdle has been very much reduced in diameter. The reduction in the 

 size of the pelvis has so narrowed the pelvic outlet that it is impossible for the urogenital and 

 alimentary tracts to pass through it and still function; this necessitates their passage outside 

 the bony arch— a condition very unusual in mammals. The eyes are so degenerate that 

 they are doubtless able to function only in perceiving the difference between light and 

 darkness. To compensate for the deficiency in sight, special tactile organs have been devel- 

 oped on the snout and on the margins of the fore-feet.— Bertram G. Smith. 



937. Steinach, E. Verjiingung durch experimentelle Neubelebung der Alternden 

 Pubertatsdriise. [Rejuvenation through experimental revitilization of the senile sex glands.] 

 68 p., 9 pi. Julius Springer: Berlin, 1920. 



938. Thomson, J. A. Modern study of heredity. [Rev. of: Morgan, Thomas Hunt. 

 The physical basis of heredity. 14 X 21 cm., SOO p., 117 fig. J. B. Lippincott Co. : Philadel- 

 phia, 1919. (See Bot. Absts. 5, Entry 422.) Jour. Roy. Microsc. Soc. 1920: 354-357. 

 Sept., 1920. 



939. Tischler, G. Ueber die sogenannten "Erbsubstanzen" und ihre Lokalisation in 

 der Pflanzenzelle. [On the so-called hereditary substances and their localization in the plant 

 cell.] Biol. Zentralbl. 40: 15-28. 1920.— Resume of literature on composition and behavior 

 of chromosomes in relation to their function as bearers of Mendelian hereditary factors. 

 Discussion of their chemical composition, cytological behavior and their role in heredity.— 

 E. G. Anderson. 



940. van de Weyer, W. Hybrid Buddleias. Card. Chron. 68: 181. 1 fig. Oct. 9, 

 1920.— An account of hybrids of B. globosa with B. variabilis magnifica, and with B. Mada- 

 gascariensis. Segregations as to foliage, color, seed characters, fertility and fragrance are 

 briefly indicated. — J. M. Shull. 



