ON THE DERMAL ARMOUR OF JACARE AND CAIMAN 311 
Batrachia. At each end of this small “ mat” of connective tissue, the 
bundles, if I may so say, fray out; and at the anterior end, the 
layers, loosened in texture, bend upwards, spreading out at the same 
time to become continuous with the fibres of the “ mat” in front. In con- 
sequence of the matting under the quadrate surface of each scale, the 
dermis has a peculiar facetted aspect, quite apart from any osseous 
deposit. Where bony scutes are formed, they appear as very thin 
perforated plates in the most superficial portion of the deep layer. of 
the dermis ; so that there is a single thin layer of dense connective 
tissue above them, while below them are all the rest of the denser and 
deeper lamella of the dermis. Through the apertures in this primi- 
tive osseous plate (the rudiment of the middle layer of the future 
scute), bundles of connective tissue extend, connecting. the. deep with 
the superjacent lamelle. 
If a thin section is made and decalcified with weak acid under the 
microscope, the calcareous matter, as it is dissolved away, leaves an 
obscurely fibrous matrix of a different aspect from the surrounding 
connective tissue, and the endoplasts, or nuclei, of this matrix are 
seen each to have occupied the centre of a lacuna. 
Again, the rudimentary scute lies in the dermis as in a sort of 
pocket, the superficial and deep walls of which separate from it with 
great ease; and in good thin sections made through the dermis and 
scute, there seems to be no direct connection between the substance 
of the scute above and below, and the connective tissue with which it 
is in contact. Nor could I satisfy myself that the margins of the 
scute were continuous with the surrounding bundles of connective 
tissue. However, the specimen had been a very long time in spirit ; 
and I am unwilling to lay too much stress upon these observations, 
which tend to negative the supposition that the scute proceeds from 
the direct calcification of the connective tissue of the dermis. 
On the other hand, I must remark that horizontal sections of the 
scutes have presented oblique parallel fissures, sometimes crossing 
one another, which might readily be supposed to correspond with the 
lines of separation of ossified bundles of connective tissue. 
NoTE.—During a recent visit to Paris, my friend Mr. Busk was 
kind enough to examine the specimens of recent Crocodilia in the 
Museum of the Jardin des Plantes, with reference to certain points. 
to which I requested his attention. Mr. Busk informs me that there 
is no doubt about the transverse direction of the premaxillo-maxillary 
suture in Crocodilus rhombifer ; and his statements lead me to enter- 
tain no question that C. domdzfrons is a synonym of C. palustris. 
