A Go7itrihution to our Knoioledge of the Anatomy of Chamaeleo7is. 101 
boundary of the orbit : in the pumilus group, however, they do not meet. 
This character is not absolutely constant in the genus Chamaeleon even 
apart from the puinilus section, since C nasittus and G. gastrotaenla 
exhibit the piimilus condition; whilst G. lateralis has the pre- and post- 
frontals connected by a membrane external to the frontal, G. brevicornis 
agrees with the condition found in dilejns. There can be little doubt but 
that the dilepis condition is secondary. 
Lachrymal. — G. dilepis has a distinct lachrymal bone like most lizards, 
but no such bone is to be found in Broohesia (and in Bhampholeon) and in 
ihQ pumilus gicoxx'g. It is also absent in G. brevicornis and G. lateralis. 
Nasal. — The nasal bone in the skull of Brookesia is a large unpaired 
plate bordering the nasal opening. In all species of Chamaeleon the nasal 
bones are small and paired and do not border the nasal opening, being cut 
olf therefrom by a forward prolongation of the prefrontals. In the adult 
skull the large prefrontal fontanelle is bordered internally by the nasals, 
and is thus entirely separated from the nasal opening ; but in the young 
of ventralis the prefrontal fontanelle and the nasal opening are in open 
connection — a condition which, according to Parker, is exhibited also in the 
case of the newly hatched young of G. vidgaris, and according to Werner 
in the adult of Bhampholeon. This latter genus is said to have small 
paired nasals. In one species of the pumilus group, namely in G. 
damaranus the nasal has a transverse process passing to the pre- 
frontal and then completely dividing the prefrontal fontanelle into two ; 
otherwise the pumilus group shows in this respect no important difference 
from quilensis or vulgaris. 
Parasphenoid. — According to Parker a parasphenoid bone occurs in the 
skull of G. pumilus, but is absent from that of G. vidgaris. Siebenrock 
further describes and figures this bone in Brookesia. We have not been 
able to find any trace of the bone in G. ventralis : in this species the 
interorbital septum is thickened at the base, but shows no ossification 
whatever. 
Vomer. — An unpaired vomer is found in the pumilus group and in 
G. quilensis. In G. pumilus it is notched at both ends, but otherwise shows 
no indication of a paired origin even in young skulls. It is absent in 
Brookesia and Bhampholeon. The single vomer of Ghamaeleon is no 
doubt homologous with the paired elements of lizards to which Dr. Broom 
has assigned the name Prevomers," as they are suspected to be different 
from the mammalian vomer. 
Golumella cranii. — Mr. Boulenger states that Chamaeleons have a 
small columella, and Dr. Gadow says that this bone is present in a much- 
reduced state, partly imbedded in the interorbital septum. We have not 
been able to find any trace of the bone, and Parker noted its complete 
absence. 
