242 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXVI. 



homologous with those of the sacral region. The compressed, blade- 

 like spines of the anterior caiidals decrease rapidly in both height and 

 width antero-posteriorly to a compressed, rod-like spine on the eighth. 

 The spines gradually reduce in size posteriorly, at the same time 

 becoming more and more depressed until in the smallest and most 

 posterior they are nearly parallel with the longer axes of the centra 

 (see fig. 19). As found in No. 42S2, they persist almost to the end 

 of the tail as small bony rods with compressed ends, without expansion, 

 which extend well back over the succeeding vertebra. 



The anterior zygapophyses gradually lengthen posteriorlj'^ until, in 

 the distal caudals, as shown in fig. 19, they consist of two slender 



finger - like j)roc- 

 a.zt/g. ^_, >^=^^>-^^.#*>^N-— ;rr — i s. esses which ex- 



tend forward and 

 lap along the base 

 of the neural 

 spine of the pre- 

 ceding vertebra. 

 The posterior 

 zygapophyses o f 

 the anterior caudals slightly overhang the ends of the centra but 

 gradually come to occupy a higher position on the spine, and with 

 the increased slant of the latter, they overhang considerably. The 

 zygapophyses also grow smaller until just back of the middle caudal 

 region there is no well defined articular area, the zygapophyses simply 

 clasping the base of the spine, as mentioned above. 



The anterior vertebrae have oblique facets on both ends of the 

 centra, but in the distal region there remain only weak facets on the 

 ventral posterior ends. The anterior chevron facets are the first to 



disappear. 



Principal measurements of vertebra: 



Fig. 19. — Postekior caudal vertebra with chevrons (30th 

 TO 34th, inclusive), Camptosaurus browxi. Holotypb. 

 Cat. No. 4282, U.S.N. M. ; k nat. size ; side view ; a. zyy. 

 prezygapophysis ; ch, chevrox ; s, neural spine. 



Vertebrfe. 



Greatest length of centra. 



U.S.N.M. 

 No. 4282. 



Yale Mu- 

 seum No. 

 1877. a 



U.S.N.M. 

 No. 2210.6 



Greatest transverse diameter, 

 posterior ends. 



U.S.N.M. 

 No. 4282. 



70 



66 



Yale Mu- 

 seum No. 

 1877. c 



U.S.N.M, 

 No. 2210. 



18 

 19 

 <i21 

 22 

 22 

 23 



Remarks. 



Anterior end No. 2210 

 =22 mm. , transverse 

 diameter. 



Greatest height (with 

 spine) of No. 4282, 

 taken at center, 93 

 mm. 



Greatest height (with 

 spine) of No. 4282, 

 taken at center, 91 

 mm. 



oNo. 1877=holotype C. dispar. 

 6 No. 2210=holotype C. nanus. 



cNo. 1877 a =paratype C. diBjiar. 



d Estimated measurements from mutilated specimens. 



