856 



SCIENCE 



[N. S. Vol. XXVII. No. 700 



of individually examining practically an en- 

 tire natural group and was surprised by what 

 seemed to me the large proportion of injured 

 individuals which were able to live on in an 

 apparently normal fashion. The society con- 

 sisted of about 460 toads, of which 434 came 

 under careful observation. Of these, 22, or 

 5.07 per cent., were noticed which showed the 

 results of injury. Many of these injuries 

 were slight, to be sure, yet from the point of 

 view which Conn and Kellogg were consider- 

 ing they should be counted. The list of in- 

 jured was as follows: 



Parts of toes lost, one or both feet : 13 indi- 

 viduals. 



One or both feet crushed: 2 individuals. 

 These both were recently wounded and might 

 not have survived long. 



Old flesh wounds on arm, thigh and side of 

 body: 1 individual. 



Shank broken, healed and 1 to 2 mm. shorter 

 than normal: 4 individuals. 



One foot missing and fresh wound on ankle : 

 1 individual. 



Eight hand and foot missing: 1 individual. 

 Stumps covered with heavy callosities. In this 

 specimen the normal gastrocnemius muscle 

 weighed 0.435 g., while that of the injured 

 side weighed but 0.180 g. 



Shoulder-girdle (coracoid and clavicle) 

 broken completely across near the mid-line: 

 1 individual. This break had not healed; 

 the ends projecting ventrally under the skin 

 had become covered with heavy callosities. 



That injuries such as these are not very 

 considerable factors in non-survival is indi- 

 cated by the fact that the average weight of 

 the 22, injured specimens was not very dif- 

 ferent from that of the entire colony — 38.5 g., 

 as compared with 44.8 g. The number of 

 injured seems too small to justify the applica- 

 tion of precise methods of comparison. 



There is the possibility that the males are 

 more liable to injury than the females, since 

 the ratio of injured males to injured females 

 is as 9 : 10, while in the entire group the ratio 

 is less than 7 : 10. This is of interest in 

 connection with the fact, brought out in my 

 study on correlation, that the males are 



throughout their organization less perfectly 

 correlated than the females. Their lower de- 

 gree of structural correlation may be partly 

 responsible for their greater liability to in- 

 jury. 



But this 5 per cent, injured does not tell 

 the whole story. In addition 16 individuals, 

 or 3.68 per cent., were noticed showing struc- 

 tural " abnormalities," which would seem to 

 have been at least as serious as regards sur- 

 vival as most of these injuries, perhaps more 

 so, since the individual would be affected 

 throughout its existence, whereas an injury 

 would become a factor only after the indi- 

 vidual had probably a fair start in life. The 

 following were noted: 



One foot misshapen and small: 2 individ- 

 uals. Possibly the result of injury when very 

 young. 



One foot with six toes : 1 individual. 



One foot with four toes: 1 individual. 



One foot with three toes: 1 individual. 



Gall-bladder absent: 5 individuals. 



One lobe of liver more or less completely 

 reduced: 5 individuals. 



Ventricle deeply furrowed ventrally: 1 in- 

 dividual. Possibly the result of injury when 

 very young. 



These individuals were again nearly but 

 not quite of average weight and the males 

 were far outnumbered by the females, the 

 normal ratio of 7 : 10 being reduced here to 

 2.3 : 10. This might possibly indicate that the 

 more perfectly correlated females are the bet- 

 ter able to survive congenital abnormality. 



This gives a total then of 8.75 per cent, of 

 a natural animal group showing injuries or 

 " abnormalities " which would seem to be 

 rather serious handicaps, but which prove not 

 to be such. Probably other injured or " ab- 

 normal " specimens would have been found if 

 attention had been directed toward the subject 

 at the time of observation. 



It may or it may not be permissible from 

 the present point of view to include in the 

 list of " abnormal," six specimens of a distinct 

 "variety" distinguished by color and mark- 

 ings, odor, external proportions, character of 

 skin, etc. If these should be included as ab- 



