SYSTEMATIC REVISION 



63 



Cacops aspidephorus Williston. 

 Bull. Geol. Soc. Am., vol. 21, 1901, p. 253. 



Type: The same as that of the genus. 



Original description: This is contained in the summary of the genus 

 on page 62, and in the morphological description, page 119. 

 Revised description: Contained in that of the genus. 



Family ASPIDOSAURID/E fam. nov. 



1. Small. 



2. Occipital condyles separate. 



3. Otic notch present, small. 



4. Unknown. 



5. Unknow^n. 



6. Apices of neural spines expanded into overlapping, rugose plates, 



forming an imperfect dorsal armor. 



7. Unknown. 



8. Unknown. 



9. Unknown. 



10. Unknown. 



11. The two halves of the neural spine united. 



12. Intercentra thick, constricting the notochordal space. Lateral 



processes for the head of the rib present. 



This seems to be a well-established family characterized by the expan- 

 sion of the neural spines and the development of lateral processes on the 

 intercentra. The known specimens are fragmentary, but enough is known 

 to suggest an animal resembling Trimerorhachis in the general form of the 

 skull and probably of the body. The intercentra are much thicker than in 

 Trimerorhachis, constricting the notochord more closely, and the lateral 

 processes are unique. Facets in the same position are found on the inter- 

 centra of other Amphibia as Alegeinosaurus, and Aspidosaurus chiton seems 

 to occupy an intermediate position between these and Aspidosaurus glascocki. 

 The expansion of the spines was apparently for the same purpose as the more 

 comiplicated dorsal armor in the Dissorhophidce; specimens belonging in the 

 two families are superficially very similar in this region. 



Genus ASPIDOSAURUS Broili. 

 Aspidosaurus cliiton Broili. 

 Paleontographica. Bd. li, 1904, s. 40. 

 Type: A considerable portion of the skull and a portion of the vertebral 

 column. Nos. 84 and 85, xv, 1901. Museum of the Alte Akademie, Munich. 

 From Texas. 



Fig. 13. — A. chiton. X *■ After Broili. 



A. Two dorsal vertebrse from side, pic, pleuro- 



centrum. 



B. Apices of neural spines of three dorsal verte- 



brje. a and h, showing lateral and superior 

 surfaces; c, showing posterior and inte- 

 rior surfaces. 



Original description of the genus and species (translation of Broili's 

 abstract of the description) : " Skull triangular with a broadly rounded snout. 



