24 Notices of Memoirs — Brief Notices. 



h. The Aigialosaurid^ show already adaptations to aquatic life 

 in the structure of the foot. 



c. Aigialosauridee and Varanidae have for common (Jurassic) 

 ancestors terrestrial Reptilia, which therefore must have had an 

 organization very similar to that of the Varanidae. 



M. Dollo claims priority for these results by referring to 

 pp. 259 and 251-259 of his memoir of 1892, " Nouvelle Note sur 

 rOsteologie des Mosasauriens " (Bull. Soc. Belg. Geol., Paleont., et 

 Hydr., Bruxelles, 1892, vol. vi, pp. 219-259, pis. iii, iv). 



3. — L. DoLLO. Les Mosasauriens de la Belgique. (Bull. Soc. 

 Belg. Geol., Paleont., et Hydr., Bruxelles, 1904, vol. xviii, 

 pp. 207-216, pi. vi.) 



Contains some new observations on the Mosasaurians. The 

 following remarks on the difference between Mosasaurus and 

 Plioplatecarpus are of especial interest : — 



Mosasaurus — by its strong dentition, its lateral orbits, its thin 

 tympanic membrane, by the absence of a median basi-occipital canal, 

 by its elongate thorax, the powerful caudal fin, and the small 

 anterior fins — is shown to have been a swimming Mosasaurian, 

 living near the surface, and enabled to capture, while swimming, 

 the formidable creatures which formed its prey. 



I'lioplatecarptis — by its reduced dentition, its upward turned 

 orbits, its calcified tympanic membrane, its median basi-occipital 

 canal, its short thorax, its feebly developed caudal fin, and its 

 strong anterior fins — is shown to have been a diving Mosasaurian, 

 descending to more or less considerable depths, and feeding ou 

 small creatures. 



4. — L. Dollo. L'Origine des Mosasauriens. (Bull. Soc. Belg. 

 Geol., Paleont., et Hydr., Bruxelles, 1904, vol. xviii, pp. 217-222.) 



The author's conclusions are as follows : — 



a. Boulenger was the first to point out the relationship between 

 the Dolichosaurians and the Mosasaurians. 



6. Gorgjanovic-Kramberger has given an important contribution 

 by his description of Aigialosaurus, and by recognising that the 

 Aigialosauridfe are ancestral to the Mosasaurians. He has, 

 however, imperfectly appreciated the phylogenetic position of the 

 Dolichosaurians. 



c. The author's memoir of 1894, " Nouvelle Note sur I'Osteologie 

 des Mosasauriens," based on original, inedited materials, gives for 

 the first time the real relations between the Lacertilians, the 

 Dolichosaurians, and the Mosasaurians. For the first time also the 

 Dolichosaurians are shown to be genealogically intermediate between 

 the Lacertilians and the Mosasaurians. 



d. Williston is mistaken in assuming (Journal of Geology, 1904, 

 vol. xii, p. 45) that Boulenger and Dollo have simply adopted the 

 views of Gorgjanovic-Kramberger. 



5. The Rh^tio Bone-beds. — Mr. W. H. Wickes has published in 

 the Bristol Naturalist's Society's Proceedings (x, pt. 3, 1904) an 

 interesting and important communication on the Rh^tic Bone-beds. 



