188 THE AMERICAN NATURALIST [Vol. XLVII 



the writer has confined himself to the discussion of the details of 

 osteology and this will make the work doubly useful to students 

 who will find here an unbiased statement of the facts of struc- 

 ture of these two interesting groups of vertebrates. The work 

 will thus be regarded as a standard book of reference on the 

 forms there discussed. It may be regretted by some that the 

 author has neglected the excellent opportunity to discuss such 

 interesting factors as hyperphalangy, hyperdactyly, phylogeny, 

 reduction of structures due to aquatic life, but perhaps this would 

 be out of place in a museum catalogue and we may hope to have 

 the views of Dr. Andrews on these subjects at some other time. 

 The second volume of the series proposes to deal with the croco- 

 diles and pliosaurs of the Oxford clay. The work will be looked 

 for with much interest. 



In a recent paper on Edestus 5 Dr. O. P. Hay discusses a re- 

 cently acquired specimen of this interesting Carboniferous shark 

 from the Des Moines Stage of Iowa, discovered in a coal mine 

 near Lehigh some 18 years ago by a miner. The specimen 

 shows the interesting relation of the so-called spines which have 

 been assigned various places by various writers. The specimen 

 seems to leave no doubt that the objects regarded hitherto as 

 spines are in reality the mandibular and maxillary cartilages of 

 a peculiar shark. Portions of the nasal and post-nasal cartilages 

 are preserved and Dr. Hay indicates a depression as the olfactory 

 pit. The cartilages are so crushed that the nature of the orbital 

 cavities can not be determined. The maxillary cartilage is some- 

 what larger than the mandibular, as in the modern sharks. The 

 paper is a very interesting contribution to the subject of Paleo- 

 zoic sharks. He suggests that the forms Toxoprion, Helicoprion 

 and Lissoprion, at present known only from detached pieces, 

 may in time prove to have the relations exhibited by the present 

 new species of Edestus; a relation which Dr. Eastman has claimed 

 for some time obtained in the forms. 



A new mosasaur is indicated by Charles W. Gilmore 6 based on 

 imperfect remains from the Cretaceous of Alabama. Mr. Gil- 

 more is inclined to establish a new genus on the characteristic 

 form of the teeth of the new form. He calls the new genus Globi- 

 dens, deriving his name from the Latin globus and dens, con- 

 trary to the usual custom of employing Greek roots for generic 



5 Proc. U. S. Natl. Museum, 42, 31-38, pis. 1-2, April 25, 1912. 



"Proc. U. S. National Museum, 41, 479-484, pis. 39-40, January 31, 1912. 



