526 



SCIENCE. 



[N. S. Vol. XXIII. No. 588. 



hunger, or another cause, crops the cerata 

 until none remain. 



Fundulus at first is excited in the pres- 

 ence of Eolis, but on longer acquaintance 

 will take detached appendages if offered. 

 I have never seen a Fundulus repeat this 

 act, though it will devour, even after hav- 

 ing taken detached cerata, an Eolis devoid 

 of them. This seems to indicate that the 

 colors of the appendages are warning 

 colors. 



The elaborate preparations made by the 

 cnidophore sacs for receiving and storing 

 the nematocysts indicate the advantage to 

 Eolis of ridding itself of these structures. 

 Probably their use as weapons, in cases in 

 which they so serve, is secondary and acci- 

 dental, the real and original function of 

 the cnidophore sacs being the elimination 

 of the nematocysts. 



The Seiise Organ of the Bill and Lateral 

 Line of Polyodon Spathula: Henry F. 

 INachtrieb, Univei'sity of Minnesota. 



Correlated. Abnormalities in the Scutes and 

 Bony Plates of Chelonia: H. H. New- 

 man, University of Michigan. 

 An examination of the carapaces of large 

 numbers of Graptemys geographica and 

 Chrysemys marginata show that there is 

 always a precise correlation of supernu- 

 merary or deficient scutes and plates of the 

 marginal series. In the neural series corre- 

 lation is frequent between extra procaudal 

 plates and the supernumerary scutes of 

 that region. 



No correlated abnormalities were found 

 in connection with the true neural or costal 

 plates which are produced by periosteal 

 expansions of the ribs and neural spines of 

 the vertebrae. 



Correlations occur only in regions where 

 plates of dermal origin exist— in the mar- 

 ginal and procaudal regions. This may be 

 used as evidence in support of the theory 

 that there existed at one time a dermal 



carapace composed of tubercular or flat- j 



tened chitinous elements (scutes) with i 



cores or supports of dermal bone. The 5 



rapid secondary expansion of ribs and j 



neural spines rendered these dermal bony .j 



supports superfluous in the large central 1 



portion of the carapace, but in other re- j 



gions they persisted as the marginal, ! 



nuchal, procaudal and pygal plates. ^ 



In these regions, then, we should not be j 

 surprised to find correlated recurrences of I 

 lost scutes and plates, since a genetic con- 

 nection exists. The procaudal and pygal ' 

 plates are distinctly in serial homology 

 with the dorsal processes of the tail of 1 

 Chelydra, leading to the belief that such i 

 processes at one time extended much fur- \ 

 ther forward. . ; 



Vestiges of dermal bones in the mid- ''. 



neural region of the carapace were found : 



in Graptemys in just the places where they i 



would be expected— beneath the keels of ' 

 the second, third and fourth neural scutes. 



A considerable amount of additional evi- i 



dence in support of this view will appear | 

 in a paper now in press. 



The Production and Control of Infertility '■ 



by Inbreeding: W. J. Moenkhaus, Uni- [ 



versity of Indiana. i 



The Direction of Differentiation in a \ 



Regenerating Appendage: Charles j 



Zeleny, University of Indiana. ' 



The problem of the direction of differ- ! 



entiation in a regenerating appendage was \ 



studied in the antennule of the common j 



brook sow-bug, Asellus, which is excep- ' 



tionally favorable because of striking and i 

 constant differences in the segments. It 



was found that the visible differentiation i 



starts at the basal and terminal ends and '. 



proceeds toward the middle of the regen- j 

 erating tissue. The basal differentiation, 



however, appears slightly in advance of the ^ 



terminal one. ' 



