No. 2.] SCAPULAR AND PELVIC ARCHES. 241 



is apparently no clavicle, as may be seen by comparing the 

 figures given in the present paper. Neither Miiller nor Dum^ril 

 and Bibron detected the rudimental pelvic arch. This appears 

 to have been for the reason that they studied only a dried 

 skeleton preserved in the Museum of Paris, from which this 

 part had been lost by the preparateur. 



AMPHISBiENIDiE. 



AMPHISB.ENA occiDENTALis Copc. PI. XIII, Fig. 1 3. Wes- 

 tern Peru. Not previously described. 



No scapular arch nor limbs ; a rudimental pelvic arch. Pel- 

 vic arch. This consists, in this species, of a slender bone in the 

 abdominal wall, a little in front of the vent on each side, which 

 is directed forwards and inwards, but without meeting its mate 

 on the middle line. It has no articular connection with any 

 other element. In Amphisbcsna alba this element is similar, but 

 is relatively shorter and more as figured by Furbringer in the A. 

 ftdiginosa. This species has also, according to Fiirbringer, a 

 very rudimental scapula. 



Rhineura floridana Baird. PI. XIII, Fig. 14. Florida. 

 Not previously examined. 



No scapular arch nor limbs ; rudiments of a pelvic arch. 

 Pelvic arch. This consists, as in the species of Amphisbaena, of 

 a single, simple, bony rod on each side of the vent. It is more 

 longitudinal in position than the corresponding element in Am- 

 phisbaena. It resembles somewhat the corresponding parts (fig- 

 ured by Furbringer) in the Lepidostermtm microcephahim. 



Observations on Annulati. The wide diversity between 

 the pelvic structure in Chirotes, as compared with that of Am- 

 phisbaena, emphasizes the evidence furnished by the scapular 

 arch, in favor of regarding it as representing a family distinct 

 from the Amphisbaenidae. Even with the pelvic elements of 

 Chirotes before us, it is difficult to be sure of the homology of 

 the corresponding part in Amphisbaena and Rhineura. It can 

 only be one of the two inferior elements, or femur. Against the 

 latter supposition, which is suggested by the structure of the 

 Anelytropsidae, its anterior position is strong evidence. For 

 the reason that it approximates closely the vent, its claim to be 

 ischium is rather stronger than the supposition that it can be 



