Dr. A. Strauch^s Catalogue of Geckos. 387 



tion to that of fishes, by the structure of the limbs, although 

 limbless forms occur in both classes. Dr. Strauch proposes 

 instead to group together the degraded forms ; but I must 

 urge that to me they seem to be the ends of diverging series 

 of forms. This explanation answers also Dr. Strauch's objec- 

 tion that I have mixed up the families at random ; it has never 

 been in my mind to form a continuous linear series of families ; 

 contrary to what Dr. Strauch appears to think, I believe such 

 a work to be impossible. 



Dr. Strauch is at a loss to find the reason why the Pygo- 

 podidse are placed among the forms with non-dilated clavicle. 

 " Ferner ist es mir nicht gelungen," he says, " zu eruiren, 

 welchem Princip Herr Boulenger bei Bestimmung der K,ei- 

 lienfolge fiir die einzelnen Faaiilien seiner Unterordnung 

 Lacertilia vera gefolgt ist, und was ihn z. B. bewogen hat, die 

 Familie Pygopodidaj, deren Reprasentanten bekanntlich keine 

 Vorderextremitaten und folglich auch kein Schliisselbein 

 besitzen, gerade zu der Gruppe mit einfacher, am proximalea 

 Ende nicht erweiteter Claviculen zu rechnen." The reason 

 is simply that, in spite of the absence of fore limbs, the Pygo- 

 podida3 have a clavicle which is not dilated proximally, and 

 that they present the characters enumerated in the heading of 

 the group alluded to. 



I append the following figures which represent the shape of 

 the clavicle in the Pygopodoid genera Pygopus and Lialis 



3 



Pectoral arch of 



1. Pygopus lepidopus. (After Fiirbringer.) 



2. Lialis Burtonii. (Ditto.) 



3. Lygosoma prcepeditum, an apodal Scmcoid from Australia. 



cl, clavicle ; icl, interclavicle ; cor, coracoid ; sc, scapula ; «s, supra- 

 scapula ; st, sternum. 



