230 



PROCEEDINGS^ OP THE NATIONAL MUSEUM. vol. xxxvt. 



a.zyg 



p.zyg 



p.zyg 



present in the cervicals of Camptosaurus unless the weak, median, 

 crest-like ridge found on the posterior elements might be interpreted 

 as such. Dorsally the neural arch consists of a broad, transversely 

 rounded surface which extends backward and upward, the posterior 

 termination giving off the divergent branches of the postzyga- 

 pophyses. The height of the arch gradually increases posteriorly. 

 Posteriorly just below the junction of the posterior zygapophyses is 

 a pit-like foramen leading forward into the neural process. While 

 this foramen is present in all of the cervicals pertaining to Cat. Nos. 

 4282 and 5474, U.S.N.M., and in the type of C. dhpar, No. 1877, 

 Yale Museum, they are entirely lacking in the cervical region of Cat. 

 No. 5473. U.S.N.M. 



Fig. 14 (1 and 2) shows the side and front views of the eighth cer- 

 vical of Cat. No. 4282. U.S.N.M.. which may be considered typical 



of the vertebrae of 

 the i^osterior part of 

 the neck. 



Marsh has given 

 the united length of 

 the nine cervical 

 vertebrse in the liolo- 

 type of C. (lis par as 

 565 mm. The com- 

 plete cervical region 

 of No. 5473 (see 

 Plate 12) measures 

 590 mm. and No. 5474, 440 mm. The principal measurements of the 

 cervicals of Camptosaurus will be found in table on pages 242 and 243. 

 Dorsal rertehrw. — As mentioned previousl}^ there are 16 dorsals 

 present in the vertebral series of both Cat. Nos. 4282 and 2210, 

 U.S.N.M. It is true, as found, there Avere interruptions in the series, 

 i. e., not all were found articulated, but after a critical study of the 

 two columns it appears quite probable that 16 will be found to be 

 the correct number. It can not be stated definitely from the known 

 material, but the evidence, at least, points very strongly to the shorten- 

 ing of the presacral series by at least five vertebrae from the number 

 given this animal by Professor Marsh in his restoration of Campto- 

 saurus dispar. (See Plate 18.) 



Th£ first dorsal— In specimen Cat. No. 4282, U.S.N.M., the first 

 dorsal was, fortunately, found interlocked by its zygapophyses with 

 the last cervical. As mentioned previously, the first dorsal, and 

 cervicals seven, eight, and nine, were taken up in a single block of 

 matrix (see Plate 6, original field numbers 76, 83, 78, and 77), and 

 reached the laboratory occupying their original relative positions. In 



Fig. 14. — (1) Eighth ckrvical veutebua of Camptosau- 

 nus BROWNi. IIOLOTYPE. CAT. No. 4282, T'.S.N.M. ; J 



NAR. SIZIO, .SIDE VIEW; (2) ANTERIOR VIEW OP SAME; (l 

 Zyg. PREZYGAPOPHYSES ; d, DIAPOPHYSBS ; nc, NEURAL 

 CANAL ; p, PAUAPOPHYSES ; p. Zl/ff, POSTZVGAPOPHYSES ; S, 

 NEURO-CENTRAL SUTURE. 



