48 CASE. [VoL. XIV. 
ebenso bei 7halassochelys, dass aber bei Chelonia, Lepidochelys, 
und Colpochelys im allgemeinen nur eine Klaue vorkommt. 
Dermochelys besitzt gar keine.” 
He showed that the presence of peripherals in Profostega and 
Protosphargis was no longer to be questioned. 
In reply to Boulenger’s paper he brought forward additional 
evidence of the relationship between Dermochelys and the 
Chelontidae. He concludes (p. 190): “Ich habe friiher [ Sczence, 
1888] die Vermutung ausgesprochen dass Dermochelys von 
einer Form der Pixzata mit volkommenem Riicken- und Bauch- 
schild abstamme, wahrend ich annahm, dass Protostega und 
Protosphargis von den Chelonitdae durch Vermittlung von 
Allopleuron (Chelonia Hoffmant) sich entwickelt haben. Es 
scheint mir jedoch wahrscheinlicher, dass Dermochelys und 
Psephophorus direkt auf Protostega- oder Protosphargts-ahnliche 
Formen zuriickfiihrbar sind, und dass der mosaikartige Panzer 
moglicherweise eine Neubildung darstellt.” Again: “ Dariiber 
aber ist kein Zweifel, dass Dermochelys und Psephophorus keine 
urspriinglichen Formen sind, sondern dass sie von wahren 
‘Thecophoren’ und zwar von den ‘Pinnaten’ abstammen, um 
mich hier dieses Ausdrucks zu bedienen.”’ 
Dr. Baur has since expressed his belief that the carapace of Der- 
mochelys was not formed, as he formerly supposed, by the break- 
ing up of the plates of the original carapace, but by a secondary 
ossification of the integument after the neurals and costals had 
disappeared, the state observed in Protostega and Protosphargis. 
The matter stood thus unsettled before the present speci- 
mens were known. They clearly show Protostega to be an 
intermediate form; but was it a step inaseries advancing from 
Dermochelys to the Cheloniidae, or a specialization of the primi- 
tive Chelonitdae toward Dermochelys ? I believe the latter. 
There can no longer remain a doubt as to the possibility of 
referring the skull of Dermochelys to that of the Chelontidae , 
Protostega fills the gap completely. The lost neurals and 
costals of Dermochelys are seen in the expanded ribs of Proto- 
stega, and the vanished peripherals are strong in the cretaceous 
genus. The lack of a process on the nuchal of Protostega 
speaks strongly for the origin of Dermochelys by specialization 
