Miscellaneous. 353 



me as to the existence of some of the characters which I have indi- 

 cated as diagnostic of the Pleurodiran Chelonians. 



First, my statement that " The mandible articulates with the 

 skull by a condyle fitting into a concavity of the quadrate " is fol- 

 lowed by the remark that " Dasselbe ist der Fall bei den Chelydridse 

 und Cinosternidse und anderen." This is evidently due to my critic 

 not having understood my meaning ; but it shows how very super- 

 ficial a knowledge he must have of the Chelonian skulls not to have 

 noticed the great difference in the articulatory region of the man- 

 dible of a Pleurodiran as compared with any other Chelonian. 

 Secondly, my statement that " The outer border of the tympanic 

 cavity is completely encircled by the quadrate" is contradicted 

 thus : — " Dies ist nicht volkommen der Fall bei Chehjmys victorice, 

 wahrend dieselbe Eigenschaft auch den Chelydridse und Trionych- 

 idae zukommt." Here, again, Dr. Baur misunderstands me ; had he 

 referred to the publication he quotes he woidd have found that I do 

 not include the Trionychida) either among the Cryptodira or among 

 the Pleurodira ; and had he taken the trouble of comparing a skull 

 of a Chelydroid with that of a Chelydoid he would have seen that 

 in the latter the ear-chambers are closed posteriorly precisely where 

 they are open in the former, and vice versa. 



I think it desirable to make this reply, because the accuracy 

 of my statements is called into question in a most offhand manner 

 by a zoologist who evidently writes on these matters without speci- 

 mens before him : and I seize this opportunity for expressing an 

 opinion on that author's recent publications on the Chelonia, 



His views as to the relationships of the Sphargidae, which have, 

 in his own writings, already undergone various modifications *, have 

 been most ably refuted by Dollo, whose criticisms have not yet been 

 answered. For my part, I have to say that the statement that 

 Dermoclielys differs from the Chelonidse only in the configuration 

 and isolation of the carapace is simply monstrous, and that Dr. Baur 

 could not have been acquainted with Dermoclielys at the time he 

 published his note. What ! he actually states that the head and 

 limbs are fundamentally the same in Dermoclielys and in the Chelo- 

 nidge ! The skull of the former bears a general resemblance to that 

 of the true turtles ; but this is limited to the shape and, to a certain 

 extent, the general constitution of the temporal roof ; in the ab- 

 *sence of the column-like processes of the parietals, descending to 

 the pterygoids in front of the supraoccipital and the prootics, it 

 differs from that of all other Chelonians. As to the limbs, in spite 

 of adaptive similarity, they differ in most important points. Thus, 

 in addition to the shape of the humerus and the proportions of the 

 phalanges, the fore limb differs in the radius and ulna being sub- 

 equal in length and placed side by side in a horizontal plane, and 

 in the fifth metacarpal, instead of the first, being the shortest. 

 The mosaic-like dorsal plates of .EretmocJielys are now admitted 



* Cf. Zool. Anz. 1886, p. 687 ; Amer. Nat. 1887, p. 89 ; Zool. Anz. 

 1888, p. 423. 



