THE YEAR'S VERTEBRATE PALAEONTOLOGY 517 



remarkable for the great variation exhibited by the bones of 

 different individuals, this feature apparently indicating that 

 these reptiles were in a state of developmental inaequilibrium. 

 A restoration of the back of the skull has been attempted, 

 which shows that the whole arrangement is adapted to give 

 the greatest possible rigidity to the quadrate — doubtless for the 

 purpose of affording a firm support for the long jaws. The 

 stapes, which, according to the author, has lost its function as 

 a bone of the internal ear, is firmly united at one end with the 

 basi-occipital, whilst its other extremity is fitted into a pit-like 

 facet of the quadrate. 



This conclusion as to the stapes (or columella) having no 

 connection with the auditory function is disputed by Dr. Louis 

 Dollo in a note published in the Bulletin de la Socictc Beige de 

 Geologic^ vol. xxi. p. 1 57, who suggests that it has a kind of 

 secondary auditory function, connected with the diving or 

 " sounding " habits of the ichthyosaurs. Such a function he 

 considers to be connected with a modification of the cerebral cir- 

 culation and paralleled by the conditions obtaining in cetaceans. 



The description b}'- Mr. C. W. Gilmore, in the March number 

 of The American Journal of Science (vol. xxiii. p. 193), of a new 

 species of Bapfanodon from the Jurassic of Wyoming is of 

 interest from the fact that the remains are less incomplete 

 than those of any other known specimen of the genus. 



On account of the excessive width of the front paddle, which 

 comprises eight longitudinal rows of bones, the skeleton of a 

 new species of ichthyosaur {Ichthyosaurus platydactylus) from the 

 Chalk of Kastendamm, Hanover, described by Mr. F. Broili 

 in vol. liv. of the Stuttgart Pala'ontographica, is of more than 

 ordinary interest. At the close of his memoir the author illus- 

 trates diagrammatically the fact that in the Liassic ichthyosaurs 

 the front paddles and tail-fin are relatively much larger than 

 in the Cretaceous species, this apparent loss in the latter of 

 propelling power being compensated by an increase in the 

 width of the fore-paddles. 



Considerable importance attaches to an account of the 

 Cretaceous pliosaurian genus BracJiaucJienius given by Mr. S. W. 

 Williston in No. 1540 (vol. xxxii. p. 477) of the Proceedings of 

 the United States National Museum. Brachauchenius, w^hich is 

 known from West Kansas, is regarded by its describer as closely 

 related to Pliosaurus, from which it differs in having single- 



