299 
The right parietaleisnormal. Nothing is known to me about the source 
of the skull. It is now in the collection of the Gymnasium Eras- 
mianum at Rotterdam. HxrprıckA too mentions some very dubious 
sutures and quite admits the difficulties of a right decision, 
whether fracture or suture. The interparietale of Cavia, if developed 
independently, generally has the shape of a pentagon. The latter 
comes about more or less clearly by symmetrical right and left bends 
in the sut. lambda, about in the middle. We often see the same in 
human embryo’s of the 6th, 9th and 10th month. Compare for in- 
stance RANKEsS (1) pictures on pp. 160, 161, 162, 163, 167, 169 
and 63. Now in these embryo’s on the spot where the sut. lambd. 
makes a bend, Ranke often finds rests of the 
sutura parietalis which extend more or less far to 
the front, over the parietale. Hereby see especially 
p- 63 of Ranke (1) and compare the 5 figures 
with the explanation at the foot of them. If we 
could dispose of a great number of skulls of Cavia, 
we should quite possibly find rests of the sut. par. 
in some specimens, in the same place, just as 
RANKE found in human skulls. Especially em- 
bryological material from Cavia would undoubtedly 
be of great use to us. In the specimen of Cavia 
represented in fig. 6 we do really see an incision 
in the parietale, though a swall one, commencing 
at the bend in the sut. lambd. And just on the Fig. 6. 
very parietale that shows the dividing! Further 
examinations must make out whether my supposition is right. It 
seemed important enough to me just to draw the attention to it. 
That the sut. par. has been found with the Rodentia appears from 
my first article about Mus decumanus var. albus (see the list of 
literature No. 20.) 
„Die Parietalnaht ist auf fötale Anlage zurückzuführen“, says 
Ranke (1) on p. 27. He speaks about human skulls here. It has 
not yet been examined if the same can be said with regard to monkeys 
where this suture occurs much oftener thanin human beings. No more 
do we know what is the case with the other Mammals. The principal 
cause of this is the difficulty in obtaining embryological material. 
For two years I have collected embryo’s of Mus decumanus, Mus rattus, 
Mus musculus, Lepus cuniculus and Putorius putorius and I have al- 
