928 The American Naturalist. [October, 
length and size. The smallest specimens measure 38 mm., while the 
largest measure 54 mm., and are correspondingly robust as compared 
with the smaller individuals. All have apparently absorbed the yolk, 
since there is no external evidence of a yolk sack in any case. Whether 
this indicates that the egg varies in size when laid, cannot, of course, 
be determined until further opportunity is afforded to obtain still 
earlier stages. 
In those specimens which are best preserved, the skin presents 
certain features which do not appear to have been noticed by others, 
viz. : the presence of a system of lateral line organs, which differ 
somewhat in arrangement from those of other urodelous batrachia. 
There are three rows of end organs on the sides, as in other Urodeles. 
Of these the uppermost one is faint, and lies close to the middle one. 
The median one extends along the entire length of the sides, and over 
the sides of the tail. The lowermost row is most widely separated from 
its fellows of the same side, and extends only from the axilla to the 
groin, as usual in other forms. 
With respect to the terminal or end organs on the head, they are 
much less conspicuously developed than in other Urodeles, and there 
appear to be no distinct rows of them externally along the course of 
the hyoid and branchial arches, as in Amblystoina. 
The smallest as well as the largest individuals have the limbs devel- 
oped, and all have three toes, so that the limbs are evidently as fully 
developed as they will ever be at the time of hatching. In this 
respect Amphiuma differs not only from all other limb-bearing Uro- 
deles, but from the Anura as well. The fore and hind limbs also seem 
to be developed almost or quite synchronously, a feature which is un- 
There are three short, slightly plumose branchi^ set in an oblique 
row on either side of the back part of the head. There is nothing to 
indicate that they differ very widely from those of the larvse of Am- 
blystoma in their histological structure. 
The general color of the smaller individuals is darker than that of 
the larger ones. The smaller specimens are blackish bro\yn, the 
largest ones somewhat paler and also lighter on the under side of the 
body. Some specimens have a very narrow colorless stripe running 
along the median line of the belly.— John A. Ryder. 
The Acquisition and Loss of Food- Yolk, and Origin of 
the Calcareous Egg-shell.— The discovery of a form of Peripatus 
with a mmute egg, without yolk, and a sort of placental development, 
