FRESH FACTS. 



Influence of Cold on Development. Oskar Schultze. " Ueber die 

 Einwirkung niederer Temperatur auf die Entwickelung des Frosches," Zweite 

 Mitteilung, Anat. Anzeig. xvi. 1899, pp. 144-152. Prof. Schultze published a 

 communication on this subject in 1895, in which he stated that subjection to 

 zero temperature brought the development of the eggs of Rana fusca to a 

 standstill. Further experiments have, however, convinced him that this is not 

 the case. Even at zero the cell-divisions continue, though more slowly. He 

 has not been able to bring about a complete non-fatal standstill in the frog's 

 development ; if it is producible, it must be by temperature below zero. 



A Snow-Worm. J. Percy Moore. "A snow - inhabiting Enchytraeid 

 (Mesenchytraeus solifugus Emery) collected by Mr. Henry G. Bryant on the 

 Malaspina Glacier, Alaska," Proc. Acad. Nat. Sci. Philadetyhia, 1899, pp. 

 125-144, 1 pi. A somewhat detailed account is given of the structure and 

 habits of this worm, which has so remarkable a home. A very striking 

 peculiai'ity is the yellow-brown, deep chocolate-brown, or almost black colour, 

 and its opacity. Associated with it was a small Podurid, Achorutes nivicola, 

 also black, and there are other instances. " It seems probable that some factor 

 in a snowy environment lays the brand of melanism upon all the constituents 

 of its invertebrate fauna." But "zoological literature fairly bristles with 

 attempted explanations of melanism." The author discusses the physiological 

 interest of an animal which lives and grows while maintaining a body temperature 

 seldom varying much from the freezing-point of water. 



Facts of Inheritance. Ernest Warren. " An observation on inherit- 

 ance in parthenogenesis," Proc. Roy. Soc. lxv. 1899, pp. 154-158, 1 fig. 

 Dr. Warren has made measurements of successive generations of Daphnia 

 magna, which, though insufficient in number, " appear to favour the view that 

 inheritance in parthenogenetic generations resembles that from mid-grand- 

 parent to grandchildren." "If this kind of inheritance be found to hold at all 

 generally in parthenogenesis, it would be a fact of very considerable significance, 

 and might conceivably give some insight into the physiological causes of 

 heredity and variation." 



Has the Hag a Parietal Eye? F. K. Studnicka. "Zur Kritik 

 einiger Angaben fiber die Existenz eines Parietalauges bei Myxine glutinosa," 

 SB. bohmisch. Ges. Wiss. 1898 (published 1899), 4 pp. In one specimen of 

 Myxine, Dr. Beard observed in 1889 a distinct parietal eye, but Betzius, Saunders, 

 and Leydig sought for it in vain. More recently, Studnicka has joined in the 

 search, and is emphatic in declaring that there is no trace of the organ to be 

 found. 



Thyroid and Thymus of Amphibians. Hermann Bolau. "Glandula 

 thyreoidea und Glandula thymus der Amphibien," Zool. Jahrb. xii. 1899, pp. 

 657-710, 11 figs. Two kinds of thyroid occur, one with colloid vesicles, the 

 other with a connective tissue meshwork including leucocytes and blood-vessels. 

 The number on each side differs in nearly related forms, but there is never 

 more than one colloid gland on each side. In Ecaudata the gland is always 

 colloid except in Molge rusconii. The thymus is single on each side in 

 Ecaudata and Caudata, except in the larval form of Amblystoma tigrinwm, 

 which has a variable number. In Siphonops, as Leydig has shown, there are 



287 



