466 Reptilian Epiphyses 
We have no direct evidence on these points. In this connection arises the 
question of the origin of the bone which goes to form any epiphysis. 
These and many other questions relating to epiphyses still await further 
investigation. 
SUMMARY. 
(1) There are no bony epiphyses on any of the skeletal elements of the 
Chelonia. (2) There are no true epiphyses on the propodials of the 
plesiosaurs. The conelike structures at the ends of the limb bones are in 
reality portions of the diaphysis and are homologous with similar elements 
found in all other existing groups of the Sauropsida. (3) There are no 
epiphyses on the skeleton of the crocodiles. (4) Epiphyses are variably 
present on the skeleton of the Lacertilia. (5) Epiphyses are of no im- 
portance in the classification of the larger groups of the vetebrates. (6) 
Parallel characters in the lizards and mammals in the presence and 
appearance of epiphyses on various parts of the skeleton due not to 
chance but to some fundamental cause. (7) The arrangement of the 
epiphyses on the hand and foot of lizards and mammals is of genetic 
importance. (8) Epiphyses are rarely present in Sphenodon. (9) 
Epiphyses are partially of a sesamoid origin but are not sesamoid bones. 
(10) Epiphyses are not necessary for the formation of good articular 
surfaces. (11) Causes of the development of the epiphyses in the Lacer- 
tilia various. 
I wish in this place to express my hearty appreciation of the interest 
shown in my work by Drs. 8. W. Williston and F. R. Lillie, and my 
gratitude for the help which I have received from them. The work was 
done under their direction and advice. 
BIBLIOGRAPHY. 
1. Dotto, L., 84.—Sur les Epiphyses des Lacertiliens. Zool. Anz. Bd. VII. 
Jahr. IX, pp. 65, 80. 1884. 
2. ALBRECHT, P., 83.—Epiphyses osseuses sur les Apophyses epineuses des 
Vertebres d’un Reptile (Hatteria punctata), pp. 1-6. Bruxelles, 1883. 
3. Parsons, F. G., 03.—The Meaning of some of the Epiphyses of the Pelvis. 
Journ. of Anat. and Physiol., Vol. XXXVII, p. 315. 
o4.—Observations on Traction Epiphyses. Journ. of Anat. and 
Physiol., Vol. XXXVIII, p. 248. 
o5.—On Pressure Epiphyses. Journ. of Anat. and Physiol., Vol. 
XXXIX, p. 402. 
4. Moopig, Roy L., 07.—The Sacrum of the Lacertilia. Biol. Bull., Vol. xeiiie 
No. 2, July, 1907, pp. 84-93. 
5. Woopwarp, A. S., 98.—Verebrate Paleontology. p. 170. Cambridge, 1898. 
