No. 2.] SCAPULAR AND PELVIC ARCHES. 23 1 



costal articulations (Mancus), it is cartilaginous, as in the genera 

 without costals. The genera with costal articulations are also 

 the only ones with osseous scapula. So we observe a certain 

 order in the loss of parts. Thus, the part to disappear first is 

 the interclavicle (to reappear in Ophisaurus) ; second, costal 

 articulations and osseous scapula ; third, sternum, which di- 

 minishes in size until greatly reduced as in Anguis and Dopasia. 

 As regards the pelvic arch, reduction of its elements precedes 

 the loss of limbs. Thus, Mancus is the only genus where the 

 pubis and ischium meet (or in the ischium, are connected by an 

 osseous hypogastroid) on the middle line. In Opheodes, where 

 the posterior limbs are much as in Mancus, these elements are 

 separated below the pubes widely. In Pygopus, where the 

 limbs are better developed than in either, the inferior pelvic 

 elements are rudimental and widely separated, being merely 

 processes of the ilium. In the genera without limbs (Ophi- 

 saurus with a minute rudiment), this reduction is carried still 

 further, the inferior elements not being distinguished from 

 each other or from the ilium, the entire arch having a lateral 

 position. Miiller remarks of these parts in Pseudopus, Ophi- 

 saurus, and Anguis, that they are "zwar sehr ahnlich." The 

 order of degeneracy, then, in the pelvic appendages in the Dip- 

 loglossa, is, first, reduction of inferior pieces ; second, loss of 

 limbs ; third, fusion of all the elements into a single lateral 

 bone. 



LEPTOGLOSSA. 

 Teid^. 



Propus vermiformis Cope. PI. XIII, Fig. 10. From the 

 Upper Amazon in Equador. Not previously examined. 



Scapular and pelvic arches present ; anterior limbs only, and 

 these minute. 



Scapular arch. All the elements present, but the sternum 

 represented by a narrow longitudinal cartilage, and the inter- 

 clavicle without lateral processes. Clavicle osseous, distally sim- 

 ple ; suprascapula cartilaginous ; scapula and coracoid, osseous. 

 Coracoid deeply twice emarginate, the emarginations occu- 

 pied by the coracoid cartilage. Sternum with two costal artic- 

 ulations. Fore limbs consisting of humerus and rudimental 

 ulnoradius. 



