Members of the Aquatic Salamander. 87 



arises a flattened conoid projection, the rudiment of the foot. 

 This last growth occupies about three days, and seldom exceeds 

 half a line in length, this bearing still less proportion to the part 

 of the original member which it represents. 



A day or two after the growth of the foot is completed, and when 

 the stump and new growth together are equal in length to the 

 original first joint, two vascular spots are observed in the extremity 

 of the new member, from which two knobs, the rudiments of the 

 phalanges of the second and third toes, soon push forward. In a day 

 or two more appear in the same manner, in succession, those of the 

 first, fourth, and fifth, according as it may be the anterior or pos- 

 terior extremity. This process is repeated at certain intervals, 

 until the growth of all the phalanges is terminated, but of the same 

 diminutive size as the other parts of the new extremity. This sel- 

 dom occurs before the fiftieth day from the date of the cicatrix. 



About the sixtieth day the whole length of the new growth and 

 stump together is equal to only half of the original limb, the stump 

 and new growth of the first joint being about two-thirds the length 

 of the original one, the leg about three-fifths, the foot about one- 

 third, and the toes about one-sixth, the diameter of the leg about 

 one-half that of the original one, and the breadth of the foot about 

 one-third. 



Whilst the growth of the lower joints is taking place, the pro- 

 cess of organization is going on in the superior ones, so that when 

 the growth of the second joint is completed, the first has acquired 

 a certain degree of firmness to give it support. About forty days 

 from the period of cicatrization, we find more than two-thirds of 

 the first joint occupied by a solid and central part. This central 

 part is an elastic substance, resembling cartilage in appearance. 

 It is transparent, except in some points towards the superior end 

 where a cloudy white deposit is observable. Surrounding this 

 some fibrous structure like muscular is to be seen, and the re- 

 mainder, except the cutis, which is nearly organized at an earlier 

 period, about the forty-third day, is of a soft gelatinous nature. 

 In the new growth neither the trunks of the blood-vessels nor the 



