1000 The American Naturalist. [November, 
The paroccipital has been described in Sphenodon by me in 1889° in 
the following words. “In the old animal supraoccipital, exoccipitals, 
paroccipital, petrosals are united, but on the young all these elements 
are free. There is much cartilage between the supraoccipital and the 
petrosal and paroccipital. The paroccipital is united to the exoccipital 
by suture, the elements in question of a young Sphenodon resemble 
those in Chelone and especially in Ichthyosaurus.”’ I may state here, 
that in a skull of Sphenodon, of 50 mm, in length from anterior end of 
premaxillary to occipital condyle, the suture between exoccipital and 
paroccipital is quite distinct, and also the characteristic Y-shaped 
sutures between the paroccipital, supraoccipital and petrosal. 
Siebenrock* has independently, not knowing my paper in the Journal 
of Morphology, found out the same in Sphenodon and has given very 
good figures of the conditions. He has also shown in an absolutely con- 
vinecing way,’ that in the Lacertilia the paroccipital process is also 
homologuous to the paroccipital, and has given excellent figures demon- 
strating it. These two papers were mentioned by me in the paper 
published in the Anatomischer Anzeiger, discussed by Prof. Cope, but 
he certainly did not consult the papers, which are easily accessible. 
After this demonstration of the free nature of the paroccipital in 
Sphenodon I think Prof. Cope will have to give up his view on the 
homology of the paroccipital of the Testudinata with the squamosal of 
the Lacertilia. I do not understand, how Prof. Cope could fall into 
such a fundamental error. We know since Hallman and it has since 
been redemonstrated dozens of times, that in the Reptilia and 
Birds, the semicircular canals of the ear are placed into 3 bones: 
1, the petrosal ; 2, the supraoccipital and 3, the paroccipital. These 
3 bones come together and form that exceedingly characteristic Y-shaped 
suture, first mentioned by Hallman, and fully discussed by Huxley in 
his lectures on the Elements of Comparative Anatomy, London, 
1864. 
He already stated in his Croonian Lecture: “ when the petrosal, mas- 
toid (paroccipital) and squamosal are determined in the turtle, they 
* Baur, G. On the Morphology of the Vertebrate Skull. Journ. Morph., III, 
1889, pp. 467—468. 
*Siebenrock, Friedrich. Zur Osteologie des Hatteria—Kopfes. Sizungsberichte 
d. Kais. Akad. Wiss. Wien. Mathem. naturw. Cl. Bd. CII, Abth. I, Juni, 1893, 
pp- 7-10. Pl. fig. 3. 5. 
*Siebenrock, Friedrich; Das Skelet der Lacerta simonyi Steind., und der 
Lacertiden familie überhaupt ; Sizungsb. d. Kais. Akad. Wiss. Wien. Mathem. 
naturw. Cl. Bd. CIII, Abth. I. April, 1894, pp. 4-9, Fig. Pl. III. 
