RECENTLY DISCOVERED TERTIARY VERTEBRATA OF EGYPT. 305 



Zeiiglodonts has frequently been doubted, there seems much to be said 

 in its favor. This (question has lately been discussed by Fraas and 

 b}^ Abel. 



Remains of birds are very rare, and with the exception of frag- 

 ments of the skeleton of a heron-like wader, the only specimen of 

 importance is the distal end of a tibio-tarsus, which is interesting, 

 because it shows that probably a true Ratite {Evemo-pezns) existed 

 in the Eocene in this region, and may be the ancestral type from 

 which the Struthiones and ^Epyornithes sprung — numerous common 

 characters between the two groups having been pointed out by Burck- 

 hardt. A relationship with the South American Rheas is also possi- 

 ble. On the other hand, this bird maj^ be merely another instance 

 of the results of retrogressive change, leading to loss of flight and 

 increase of size in some group of Carinate birds, such as has happened 

 in the case of the Stereornithes and Gastornithes. 



Among the Reptilia no very important new forms have been dis- 

 covered. In the Middle Eocene remains of large and probably 

 marine snakes are found, one of these {GigantopMs) having probably 

 attained a length of 30 to 40 feet. Another {Pterosphenus) is of 

 interest, because a closely allied species is found in North America 

 also associated with Zeuglodonts. From the same horizon there have 

 been collected remains of numerous Pleurodiran tortoises, a group 

 formerly Avidely spread, but at the present day found only in the 

 southern hemisphere. The most remarkable of the Egyptian Pleu- 

 rodires is Sfereof/cni/s, in which the palate and mandible are modi- 

 fied to form broad, crushing surfaces, probably for breaking the 

 shells of the animals which formed its food. In the Upper Eocene 

 beds Pleurodiran tortoises are likewise found, the modern genus 

 Podocnemis being represented b}^ several species ; but at this horizon 

 the most notable chelonian is a gigantic land-tortoise {Testudo 

 amnion)^ shells of which are comparatively numerous. This species 

 approximates most nearly to the Aldabara and Madagascar giant 

 tortoises among living forms. Numerous Crocodiles are found both 

 in the Middle and Upper Eocene, and include both long and short 

 snouted forms. One {Tomistoma gavialoides) seems, to some extent, 

 to bridge the gap between the true Tomistoma and the Gharial. 



Remains of fishes are found in several horizons, but none are of 

 special interest. From the Middle Eocene are several peculiar saw- 

 fishes, and also several large Siluroids, which are curiously like spe- 

 cies now existing in the Nile. 



From the above account it will be gathered that a considerable 

 number of Tertiary vertebrates are already known from Egypt, and 

 include forms of great interest. At the same time, these must con- 

 stitute a mere fraction of the faunas that have inhabited this region, 



SM 190G 20 



