43 



position to be occupied by bnne, which are more closely group- 

 ed together at the points where the joints are destined to appear. 

 The lower extremity is, in fact, at this time a fin. The upper 

 extremity is in a similar condition, presenting, however, only 

 three rows of cartilaginous cells, united by a membrane. As 

 this condition of the extremities exists in different families, 

 Prof. A. thinks that the present grouping of all web-footed 

 birds together, may be incorrect ; particularly since they differ 

 as much among themselves in other respects as they do from 

 Land birds. lie found that the bill of the immature Robin 

 resembled that of a Vulturine bird, being straight near the base, 

 and curved at the extremity, the upper mandible being longer 

 than the lower. This would seem to indicate that the Vulturine 

 form is a lower type than it has usually been considered. This 

 appeared to derive confirmation from the great resemblance of 

 the bill of some of the Water birds to that of some of the Vul- 

 turine family, that of the genus Lcsti^is, for example. Some of 

 the birds of prey also have another point of resemblance to 

 Water birds in a rudiment of a web between two of the toes. 

 Hereafter, birds having all their toes directed forwards, must be 

 regarded as of a lower type than those which have one directed 

 backwards ; as, for instance, the Pelicans and Cormorants among 

 Water birds, and the genus Cypselus among Swallows. From 

 the result of his examinations of the embryos of birds, Prof. A. 

 had recently, before a scientific society, ventured to predict that 

 hereafter, among the higher Mammalia, the foot of the embryo 

 would in the same way be found to be webbed, like that of the 

 Seals and Cetacea. Prof. Jeffries Wyman immediately after- 

 ward confirmed the truth of the prediction in the case of the 

 foetus of a Cat. A similar appearance had been figured as ex- 

 isting in the human embryo, but its philosophical bearing had 

 not been before noticed. 



Dr. Cabot read a statement of the comparative measure- 

 ments of the American and European Oyster-catcher. His 

 observations tend to confirm the opinion of the distinctness 

 of the two species, which have sometimes been confounded 

 with each other. 



