490 The American Naturalist. [May, 
the condyle of the quadrate bone, being much elongate in the direc- 
tion of the longitudinal axis of the body, and, in fact, nearly four 
times as long as the opposite articular surface.’’ 
Exactly the same description is given by Brühl :3 ‘‘ Der Hatteria 
Unterkiefer setzen wirklich in jeder Hälfte nur vier elemente ztisammen : 
1. dentale, d.; 2. articulare, ar.; 3. coronoideum, cor.; mit einen 
massigen processus coron.; und 4. marginale, marg. (mihi = angulare 
autor.=spleniale Owen, Günther); die sonst bei Echsen meist vor- 
kommenden Mehrstiicke ; 5. ecto-complementare, ec. cp. (mihi supra 
angulare autor.) und 6. endocomplementare, en. cp., auch operculare, 
Op., fehlen bei Hatteria spurdos.’’ 7 
In a lower jaw of Sphenodon (length of each ramus 56 mm.) I find 
all the six elements of the Reptilian lower jaw represented. The whole 
arrangement, however, is only comparable with that seen in the Testu- 
dinata and not with that of the Squamata. 
The dentary, coronoid, and angular (splenial Günther, marginal 
Brühl) are described correctly by both Günther and Brühl. The 
remaining portion of each ramus is considered as articular. In the 
specimen before me this portion plainly consists of three elements, — 
an articular, splenial, and supraangular. 
Thé articular is a small element, only visible from above and very 
little from behind. It is surrounded by the splenial on the inner and 
the supraangular on the outer side; it is very much like the corre- 
sponding element in the Testudinata. The supraangular is that portion 
of Giinther’s and Briihl’s articular which is seen on the outside and 
inside. It is connected with the articular, the splenial, the angular, 
the dentary, and the coronoid. Between this element and the coronoid 
the foramen is placed. The splenial is the inner portion of Giinther’s 
and Briihl’s articular. It is connected with the articular, supraangular, 
angular, and coronoid. We have therefore a condition which 1s 
typically that of the Testudinata. In all the Testudinata, however, the 
angular separates the splenial and supraangular behind ; in Sphenodon 
the splenial and supraangular meet at the posterior lower end of the Jaw. 
The structure of the lower jaw in Sphenodon gives another support 
to the opinion of the affinity between Rhynchocephalia and Testudi- 
nata.—G. Baur, Clark University, Worcester, Mass., April Sth, T89I- 
On the Development of the Male Copulatory Organs 17 
Snakes.—Although the adult anatomy of the male copulatory organs 
in snakes has been carefully worked out by Neumann * and others, very 
3 Brühl. Reptilienkopf. Wien, 1886, Tafel p. CXLVIIL., Figs. 12, 13, 17, 18, 19 2° 
* Begattungsapparat der Schlangen, Leipzi 
