76 STATISTICAL METHODS. 



Lower Animals. 



ANTIMERTCALLY SYMMETRICAL ORGANS: 



Paired organs. Number of Miillerian glands on R. and L. 

 fore legs of swine, Davenport and Bullard, '96; R. and L. 

 fins of fishes, Duncker, '97, '00; number of coxal pores on R. 

 and L. legs of the centipede Lithobius, Williams, '03; R. and 

 L. dimensions of Gelasimus, Yerkes, '01, Duncker, '03; num- 

 ber of teeth on R. and L. jaws of Nereis, Hefferan, '00; 

 breadth of R. and L. valves of Pecten, Davenport, '03 b ; 

 skeletal spicules on R. and L. half of Echinus larva. 



Subject and Relative. r 



Length R, and L. sides of carapace, Gelasimus 947 .003 



" " " M meropodite, first walking leg 918 .005 



Breadth R. and L. valve of Pecten opercularis, Irish Sea. . . .858 .006 



Num. of teeth R. and L jaws of Nereis 820 .008 



" " fin-rays R. and L pectoral, Acerina 710 



" coxal pores R. and L. 14th pair legs, Lithobius 69 . 02 



" " " 13th pair legs, Lithobius 686.029 



" " " 12th pair legs, Lithobius 58 .04 



" " " " " " anal pair legs, Lithobius 575.039 



Other antimeric organs: 



r 

 Num of dorsal and ventral spines, Palsemonetes vulgaris 



(Duncker, 'OQb) 380 .019 



Num. of lips and canals of the medusa, Pseudoclytia 



(Mayer, '01 ; Davenport, '02) 325 .019 



SECONDARILY ANTIMERIC ORGANS. (Median organs in 

 animals that lie on one side.) 



r 

 Num, of dorsal.and anal fin-rays in flounder, $ 651 



" " " " " " " " ? 690 



Length antero-posterior and dorso-ventral diameters, Pecten . 970 .001 



Unsymmetrical paired organs. Pleuronectes, Duncker, 

 '00; Gelasimus, the fiddler-crab, Yerkes, '01, Duncker, '03. 



Length of meropodite, R. and L. chelae of Galasimus 754 .014 



" " carpopodite, R. and L. chelae of Gelasimus 698 .017 



" " propodite, R. and L. chelse of Gelasimus 473 i .026 



Num. rays R. and L. pectoral fin, flounder, Pleuronectes, $ . .594 

 " " " " " " " " ?. .582 



" of dorsal fin-rays at which lateral line ends, R. and L. 



Pleuronectes, $ 467 



Num. rays R, and L. ventral fin, Pleuronectes, $ 243 



