96 PALEOBOTANY [Bot. Absts., Vol. V. 



711. Conklin, E. G. The mechanism of evolution. [1] Sci. Monthly 10: 170-181. 

 1920. — This is a discussion of Mendelism in which the author concludes that the law, especially 

 as regards the segregation of inheritance factors, is of universal occurrence — that there is 

 no other type of inheritance. Alternative inheritance with dominant and recessive char- 

 acters, purity of germ cells, monohybrids, dihybrids, etc., factorial theory of heredity, blend- 

 ing inheritance, species hybrids, and unequal reciprocal hybrids are discussed in relation to 

 the above conclusion. [See also next following Entry, 712.] — L. Pace. 



712. Conklin, E. G. The mechanism of evolution. [2] Sci. Monthly 10: 269-291. 

 Fig. 11-21. 1920. — This paper takes up the cellular basis of ontogeny and phylogeny. There 

 is no fundamental difference between germ cells and somatic cells. Nucleus and cytoplasm 

 are fundamentally different chemically, morphologically and physiologically. — Mitosis fur- 

 nishes the necessary mechanism for the accurate division of the cell, and the persistent iden- 

 tity of the chromosome is accepted. The suggestion is made that chromomeres are probably 

 much more constant than chromosomes. — The mechanism of heredity is to be found in the 

 germ cells. Genetics and cytology must cooperate in correlating features of the germ cell 

 with the phenomena of heredity. The similarity of chromosomes of the spermatozoon and 

 of the egg, the reduction division, the doubling of chromosomes in fertilization, the sex- 

 chromosomes, sex-linked characters, linkage of characters, chromosomal localization and 

 cross-overs are all presented as favoring the localization of the genes in the chromosomes. 

 [See also next preceding Entry, 711.] — L. Pace. 



713. Coulter, J. M. Cones of Williamsonia. [Rev. of: Arber, E. A. Newell. Re- 

 marks on the organization of the cones of Williamsonia gigas. Ann. Botany 33: 173-179. 5 fig. 

 1919. (See Bot. Absts. 3, Entry 1143).] Bot. Gaz. 68: 152. 1919. 



714. Grandori, Ltjigia. Su di un seme mesozoico di pteridosperma e sulle sue affinita 

 con forme paleozoiche e forme viventi. [On a Mesozoic pteridosperm seed and its affinities 

 with Paleozoic and recent forms.] Atti d'Accad. Veneto-Trentino-Istriana. 8:107-116. 8 fig., 

 1 pi. 1915. 



715. Grandori, Ltjiqia. Sulle affinita delle Pteropsida fossili, studio critico. [On the 

 affinities of the fossil Pteropsida.] Atti d'Acad. Veneto-Trentino-Istriana 8: 163-195. 7 fig. 

 1915. 



716. Knowlton, F. H. A dicotyledonous flora in the type section of the Morrison forma- 

 tion. Amer. Jour. Sci. 49: 189-194. Mar., 1920. — Records the presence of an Upper Creta- 

 ceous flora similar to that of the Dakota sandstone from the type locality of the Morrison for- 

 mation near Golden, Colorado. The Morrison formation has yielded a varied dinosaur fauna 

 and there has been much controversy as to whether it was of Jurassic or Lower Cretaceous 

 age. — E. W. Berry. 



717. Principi, Paolo. Le Dicotiledoni fossili del giacemento oligocenico di Santa 

 Giustina e Sassello in Liguria. [The fossil dicotyledons of the Oligocene of Santa Giustina 

 and Sassello in Liguria.] Mem. Desc. Carta Geol. d'ltalia 6: 1-294. PL 1-85. 1916 (1919). 

 — Liguria is one of the classic regions of Tertiary geology. The Oligocene of Sta. Giustina 

 and Sassello record the transition from continental to delta and then lagoonal or estuary to 

 littoral conditions of deposition followed by a recurrence of lagoonal conditions at the base 

 of the middle Oligocene and littoral again at the top of the middle Oligocene. The fossil 

 plants which are the subject of the memoir come from the basal beds or Sannoisian stage. 

 Previous accounts of this flora have been published by Sismonda in 1859 and 1865, and Squin- 

 abol in the period from 1889 to 1892 described the Cryptogams, Gymnosperms and Monocoty- 

 ledons. — The dicotyledons recorded number 339 forms, the most varied genera being Quercus 

 Juglans, Myrica, Ficus, Laurus, Cinnamomum, and Rhamnus. Eighty-six new species are 

 described in the following genera: Castanea, Dryophyllum, Quercus, Juglans, Juglandophyl- 

 lum, Myrica, Comptonia, Populus, Protoficus, Ficus, Artocarpidium, Artocarpus, Cocculites, 



