DEVELOPMENT OP THE SKULL IN THE BATBACHIA. 
131 
condyle and a flabelliform body; its basal piece ( b.hy.) is composed of simple car¬ 
tilage. 
The basi-branchial ( b.br 1 .) is a solid cartilaginous disk, witli the rudiment of a second 
( b.br 3 .) behind it. 
The hypo-branchial (Ji.br.) is a triangular plate, which passes outside the postero¬ 
internal angle of the hyoid, and has articulating with it the four normal “ extra- 
branchials” (ex.br.). They give rise near the lower end to processes that run into the 
septa on the inner and upper surface of the pouches ; these ( c.br.) are (all but the last) 
small rays, with a pedate free end : they are “ cerato-brancliials.” 
Fourth Family. “Alythle.” 
Genus Alytes. 
This Family, as enlarged by Professor Mivart (P. Z. S., 1869, p. 291), suggests 
this remark, namely, that that assemblage of characters by which the Alytina, Sca- 
phiopodina, and Uperoliina are characterised, after all only serves to faggot them 
together; and the possession of neck-glands, dilated sacrum, maxillary teeth, and 
sharp toes by Alytes in Europe, by Scaphiopus in North America, and by Hyperolius 
((Jperoleia) in Australia, proves nothing as to the genesis of these three genera. 
Before all things, in classification, natural geographical grouping has to be looked to, 
and then afterwards the modification into Families, Genera, and Species. 
All the Australian Anura I have dissected, as yet, look to me rather like branches 
of one Australian stock than scattered scions of Families and genera from distant 
geographical regions; and whilst appraising at their full value every character that can 
be discovered in any type whatever, I shall keep as far as possible the distribution of 
the types before my eyes. The Dog-faced Opossum is far nearer akin to the Kangaroo, 
in spite of his canine features and form, than he is to the true Dog of other regions. 
31. Alytes obstetricans. —Adult female; 1 inch 10 lines long. Europe. 4 ' 
The skull of this type is extremely like that of the delicate Australian Tree-frogs, 
e.g., Hijla Ewingii and H. phyllochroa (see Plate 31); whilst in the next instance, 
an Australian Frog, the skull might be taken for that of one of the “Ranidse,” and a 
not very aberrant form of the European or the Oriental species of Rana. Yet a 
careful examination of this skull will show that the skull of Alytes has some important 
points of coincidence with that of Pelodytes and Bombinator; and the Obstetric Frog 
is more likely to be one branch of the same stock as these other European kinds than 
a migrated relative of an Australian species, or the Australian species a migrated 
relative of this. 
* My specimens of this Frog are the gift of Professor Troeschel, of Bonn, 
S 2 
