68 STATISTICAL METHODS. 



<J4=2.7%, Cj5=2.6%, (7.4 = 3.0%, Bumpus, '98, Duncker, '98; 

 critical, Bigelow and Rathbun, '03; seriations of length, 

 ratio of diameter to length, ratio of aperture to length, 

 apical angle, number of whorls, color of aperture lip, and 

 depth of suture between whorls in Nassa, Dimon, '02; seria- 

 tions of shell-index and spinosity of lo in different parts of a 

 river system, Adams, '00; variability of adult Clausilia 

 laminata less than that of young, 15:13, ascribed to periodic 

 selection, although average size not altered, Weldon, '01; 

 variability of bands of Helix nemoralis in one spot of America, 

 Howe, '98; in different localities near Strasburg, Hensgen, '02. 

 Lamellibranchiata. Seriation of number of ribs of Car- 

 dium, Baker, '03; Pecten; ray-frequency, Lutz, '00, Daven- 

 port, '00, '03, '03 b ; change in proportions with age, acquisi- 

 tion of new symmetry about transverse axis; definition of 

 form units from different localities, Davenport, '03, '03 b . 



Lot. Number of Rays. 



Pecten irradians A a C 



Cold Spring Har.,L. I., R. valve 17. 353 .018 0.876 .013 5.05 .07 



Cutchogue, L. I., R. valve .... 16.534 .034 0.852 .024 5.32 .36 



Cold Spring Har., L. valve . . . 16.790 .022 0.916 .015 5.46 .09 



Cutchogue, L. valve 15.954.105 0.881.075 5.52.49 



Pecten opercularis: 



Eddystone, R- valve 17.478.029 1.000.020 5.72.12 



Irish Sea, R. valve 18.101.029 1.074.021 5.93.ll 



Firth of Forth, R. valve 17.673.027 1.117.019 6.32.ll 



Pecten gibbus- 



Tampa, Fla~,R valve 20.512.030 0.991.021 4.83.10 



Pecten ventricosus: 



San Diego, Cal., R. valve .... 19.495 .087 0.885 .019 4.55 .10 



Echiiiodermata. 



Seriation of ray-frequency in starfish, Crossaster papposus: 

 A = 12.391, C=0.788, v=6.36%, Ludwig, '98 b . 

 Coelenterata. 



Scyphomedusce. Seriation of number of tentaculocysts of 

 Aurelia aurita: n=3000, empirical range 4-15; empirical 

 mode=8, genital sacs, M'=4, range, 2-10, Browne, '95, '01. 



Hydromedusce. Seriation of number of radial canals, 

 gonads, gastric lobes, and tentacles of Gonionemus, Hargitt, 

 '01 ; radial canals and lips of Pseudoclytia pentata, Mayer, '01, 

 Davenport, '02; radial canals, etc., of Eucope, Agassiz and 

 Wood worth, '96. 



