1891.] Remarks on Reptiles Called Dinosauria. 445 
5. The quadratojugals are placed between quadrate and jugal, 
but do not touch the squamosal. 
6. The squamosals do not send down a process to join the 
quadratoj ugal. 
` 7. The quadrate is very elongate, with its lower end directed 
forwards; there is a well-developed pterygoid process. 
8. The mandible has a distinct predentary line. 
g. The dentary has a greatly developed coronoid process. 
10. The externa] nasal openings are limited by the premax- 
illaries and nasals. 
11. The prelachrymal fossz are small, and limited by the 
maxillaries, prefrontals, and lachrymals. 
12. The orbits are limited by the supraorbitals, lachrymals, 
jugals, and post-fronto-orbitals. 
Diplodocus——These notes on Diplodocus are based on the 
figures of Prof. Marsh, which, however, are not quite correct, as I 
found from the study of the original specimens. 
1. The brain-case is completely ossified; a very strong ali- 
sphenoid being present. 
2. The premaxillaries are separate, and there is no process 
extending between the nasals and maxillaries, excluding the 
maxillaries from the nasal opening. 
3. No epipterygoid (columella). 
4. The jugals are placed in the same level with the alveolar 
border of the maxillaries. They do not reach the end of the 
dental series. They are in connection with the lachrymals, post- 
orbitals, quadratojugals, and maxillaries. They bound the orbits 
only pre-inferiorly. 
-5. The quadratojugals are placed between the quadrate and 
maxillary, but do not touch the squamosal. . 
6. The squamosals do not send down a process to join the 
quadratojugals. 
7. The quadrate is elongate with its lower end strongly directed 
forward. There is a very large pterygoid process. 
_ 8. The mandible has no predentary bone. 
9. The dentary is without coronoid process. 
Am. Nat.—May.—3. 
