September 7, 1900.] 



SCIENCE. 



373 



A Study of the Variations in the Number of 



Grooves upon the Shells of Pecten irradians 



(Lam.): By Frank E. Lutz. 



The material for this study was gathered 

 from East Beach, Northport Bay, L. I., 

 during the scallop season of 1899-1900. 

 The Beach is an extremely well-protected 

 one in an almost land-locked harbor. The 

 results given by a count of five hundred 

 specimens of each valve were as follows : 



Lower valve. — Average = 17.456 ± 0.022; 

 Standard Deviation = 0.726 ± 0.015 ; Co- 

 efScient of Variability = 4.163% ± 0.888% . 



Ujyper valve. — Average = 17.110 ± 0.027 ; 

 Standard Deviation = 0.922 ±0.019; Co- 

 efficientofVariability= 5.388% ±0.115%. 



The curves obtained in both cases were 

 nearly normal — that of the lower valve 

 approaching the closer. The shells show 

 the least variability of any Pectens yet 

 studied. 



Statistical Studies on Sand Fleas : By Mabel 



E. Smallwood. 



Five hundred sand fleas (Talorchestia), 

 apparently adult, were gathered from the 

 Sand Spit at Cold Spring Harbor. They 

 ranged in length from 15 mm. to 27.5 mm. 

 The length of the antennse ranged from 5.5 

 mm. to 24.4 mm., the average was 13.01 

 mm. ± 0.14 mm. and the standard deviation 

 was 4.67. Attempts to fit a theoretical 

 unimodal curve were unsuccessful. From 

 inspection of the distribution of frequencies 

 it seems probable that the observed curve is 

 multimodal with two principal modes placed 

 so near together that their distinctness is 

 hidden, and that these two modes corre- 

 spond to two moultings. The length of 

 the tentacle is proportionately much longer 

 in the larger individuals and it seems prob- 

 able that the two recognized species — T. 

 megalopthalma and T. longieornis are merely 

 two different moults of the same species. 

 Breeding experiments are now in progress 

 to test this conclusion. 



Pedigree Mouse Breeding : By 0. B. Daven- 



POET. 



Quantitative data are being collected 

 from a colony of fifty mice of different races 

 concerning inheritance of color and other 

 measurable characteristics. Especially note- 

 worthy are the relative prepotency of dif- 

 ferent races, reversion, the skipping of a 

 generation in inheritance, the localization of 

 white patches and of the other parental 

 color-markings on particular parts of the 

 body of the offspring. The results are not 

 yet ready for publication. 



C. B. Davenpoet. 



Cold Speing Haeboe, L. I., 

 August, 1900. 



SCIENTIFIC BOOKS. 

 Tarr and McMurry's Geographies. First Book — 

 Home Geography and the Earth, as a Whole. 

 Pp. xiii + 279. Second Book — North Amer- 

 ica, with an especial full treatment of the 

 United States and its dependencies. By 

 Ralph S. Taee and Frank M. McMuery. 

 New York, Macmillan. 1900. Pp. xviii + 

 469. 



The first volume is a disappointment. The 

 authors call it ' a radical innovation,' but the 

 claim does not seem well founded. Apparently 

 they have meant to make the Home Geog- 

 raphy and the maps the features. 



Home Geography is a misnomer for the book. 

 The idea that the child ought to begin with the 

 study of forms about him is good, but not new, 

 and the idea is not realized in this volume. A 

 few sentences connect bills and valleys and 

 soils with environment ; the mountains are said 

 to look like clouds on the horizon. The rest is 

 descriptive and not Home Geography at all. 



Suggestions for further home study are ap- 

 pended to the chapters, 8 or 10 pages in the 

 280, but they are subordinate and will be neg- 

 lected by most teachers as such, especially as 

 teachers are still untrained in outdoor work. 



For instance, the first suggestion is, " Find a 

 place where men are digging a ditch or cellar, 

 to see how the dirt looks below the surface" — 

 an admirable thing to do, but the inertia of the 



