366 S. W. WILLISTON 
these genera these ribs appear to be continuous, directed backward, 
outward and upward from the median line back of the coracoids, 
and they are not at all imbricated. In this remarkable specimen 
they lie everywhere in five or six imbricated layers directed obliquely 
forward and outward, the thin external edges about one millimeter 
or a little more apart. Such an arrangement, if they be dermal 
structures, must certainly have been inconvenient-for a crawling 
creature, unless it were descending a tree! And this leads to the 
conclusion that these scutes, notwithstanding their close imbrica- 
tion and fish-like appearance, must have been ossifications in the 
connective tissue, and overlaid by the skin in life. 
The very short spines, the broad and flat zygapophyses and 
strong rib attachments suggest a slender lizard-like form for the 
living animal, one probably with long legs and prehensile feet, 
cursorial or climbing in habit. 
The name Trispondylus Williston (this Journal, XVIII, 592) 
is preoccupied; it may be replaced by Trichasaurus, nom. nov. 
