220 SPHAERODACTYLUS. 



certain anguids, without which respiration would be impossible owing to the 

 integumentary armament. 



Since this memoir was prepared for publication some time ago it behooves 

 me to comment supplementally on Noble's valuable paper The bonj'- structure 

 and phyletic relations of Sphaerodactylus and allied lacertilian genera, with the 

 description of a new genus published in the American museum novitates, 10, 

 March, 1921, no. 4, p. 1-16, 8 figs. 



In this paper Noble gives the results of his studies of the skeletal features 

 of a number of gekkoid genera made with the aid of cleared preparations. With 

 one of his conclusion I most heartily agree, namely that the Eublepharidae 

 constitute an unnatural assemblage and it is evident that the family serves no 

 useful purpose, being simply an omnium gatherum combining the end results of 

 several lines of descent not closely related. Thus the family "instead of being 

 a very ancient group as hitherto believed,. . . may be a very recent assemblage, 

 even if a conservative one." 



Noble derives Sphaerodactylus from a genetic series of which Gonatodes, 

 Lathrogecko, and Lepidoblepharis represent successive stages of modification. 

 Various internal characters are cited and illustrated to support the evidence 

 derived from a comparative study of the digital apices; this is presented very 

 persuasively and while it may be correct it is by no means certain that too much 

 stress is not placed upon fortuitous similarity. I believe that often skeletal 

 modifications are very easily brought about by changes in feeding habits or 

 through very many other causes and often even \^hat are apparently such 

 ephemeral features as colour-characters may be very conservative. In other 

 words the external facies of an organism may offer, within reasonable limits, 

 better criteria for postulating relationships than certain skeletal features. 



Noble's work on the claw-sheaths is very valuable, and while here again it 

 is possible that similarity maj' not indicate actual phyletic relationship neverthe- 

 less the probabiUty is very considerable that some such descent has taken place 

 when this evidence is taken in connection with the internal characters of hyoids 

 and girdles. 



It would be very interesting to know Mr. Noble's views on the connection of 

 Aristelligcr \^ith this series for it is almost inconceivable that this relationship 

 is not close. I strongly suspected this genus to be the closest ally of the 

 sphac redact yls. That no fossils remain to cast light upon the subject is not 

 surprising in view of the fragility of their bony skeleton. 



The sphaerodactyls are preeminently island gekkos and they probably occur 



