560 Chas. W. Hargitt. 



A Comparison of the Variations Exhibited by Ephyrce During 



Metamorphosis. 



During the current summer, 1905, I was able to secure a collec- 

 tion of about 1000 ephyrae from Waquoit Bay, a body of water 

 some ten miles east of Woods Hole, from which had also been 

 secured a portion of the previous series in 1 90 1 . Among these were 

 found 392 specimens which were just emerging into young 

 medusre. They varied in size from 7 to 14 mm. in diameter, the 

 radial canals were well differentiated, and the gastric pouches 

 easily distinguishable. There were also 218 ephyrae among the 

 number which were entirely devoid of any indications of meta- 

 morphosis, indeed, apparently but recently escaped from the 

 strobila. I was particularly glad to have an opportunity to study 

 a series of this character from a strictly local environment and 

 from the same brood, so to speak, since it afforded an opportunity 

 to test a feature of variation already referred to, namely, whether 

 varietal features existing in one stage are carried over into another, 

 or whether during a period of metamorphism there was at work 

 any selective processes. 



While the numbers examined in these cases are too small to 

 afford conclusive data on a problem of this character, they may 

 at any rate afford a fair indication as to probabilities, and when 

 taken in comparison with similar series in larger numbers, as in 

 the former case, and also in connection with the observations of 

 Browne (op. cit.), they may become correspondingly more 

 convincing. 



A comparison of the data presented in Tables IV and V will 

 show, both in relation to the percentage variation and to the 

 question of the persistence of varietal features during the several 

 phases of metamorphism, rather striking points of likeness. 

 So far as the ratio of variation is concerned it will be seen at a 

 glance that it is so nearly the same in the several cases as to pre- 

 clude the probability of anything more than slight and incidental 

 differences. For example, in Table I the total per cent of 

 variation is 26; in Table V it is 22.2; while in Table IV it is 

 22.9. Compared with the ratio obtained by Browne, which 

 for 359 ephyrae taken in 1893 was 22.6, and for 11 16 speci- 

 mens taken in 1894 was 20.9, the results become still more 

 conclusive. 



