FISHES 181 



for holding the female. It is more probable that the former 

 is the true function. 



In another British species, Raia microcellata, the teeth 

 are in the same condition as in R. clavata, flat in the females 

 and young males, pointed in adult males. 



In R. maculata the teeth are pointed in both sexes, and 

 also in R. radiata and R. circularis. 



In the long -snouted species, or Skates, the teeth are 

 pointed in both sexes, although more so in the male in the 

 case of Raia batis, the Common or Blue Skate. 



Fig. 19 Chimcera monstrosa, male. After Day. 



It is difficult to explain these facts on Lamarckian prin- 

 ciples, especially because we know so little of the habits of 

 the living fish. We cannot maintain that the teeth are 

 naturally flat, and only pointed in the males as a conse- 

 quence of their use in fighting. It is a more plausible sug- 

 gestion that in the females and young males of certain species 

 they have become flattened, because the fish have acquired the 

 habit of feeding on hard-shelled animals, namely molluscs 

 and Crustacea. The pointed teeth of the males, on this 

 theory, might be due to their use in fighting. But then the 

 question arises, how the effect of the use of the teeth in 

 fighting could counteract the use of the teeth in feeding, 



