l68 THE PERMO-CARBONIFEROUS RED BEDS OF 



but the posterior edge does not overhang the ischial border, forming a deep 

 notch. The anterior edge of the lower end of the ilium is thickened, but not 

 after the manner of Eryops. In that genus there is a sharp ridge on the inner 

 edge of the bone and the outer edge is concave, but in this specimen the whole 

 bone is convex from without inward. The cotylus is relatively higher than 

 in Eryops. 



A neural spine (plate 22, figs. 8 and 9), with the arch and transverse proc- 

 ess, and the apex of a second spine. No. 3294, indicate the presence of an as 

 yet undescribed amphibian, probably in the Une of Zatrachys or Aspidosaurus. 



The neural arch is typically that of a temnospondylus form with well- 

 developed zygapophyses and transverse processes. The spine is relatively 

 very high, fully as high as that of an Eryops vertebra of three or four times 

 its size. It belongs to a distinctively high-spined amphibian and is the first 

 indication of such a form in the Texas beds. The only other form with high 

 spines which has been regarded as showing amphibian characters is Platy- 

 histrix, from the New Mexican beds, and this probably is a reptile. The 

 exact position of the form can not be stated ; it probably belongs to the as yet 

 poorly understood line in which occur Zatrachys, Aspidosaurus, and Dissoro- 

 phus. It is noteworthy that but a single intercentrum of a temnospondylus 

 amphibian of small size was found in the large amount of material taken 

 from the bed ; this may be due to accidents in accimiulations of the material, 

 but if so it is very peculiar. I would rather attribute it to the peculiar asso- 

 ciation of animals in the bed. However, many small forms of amphibians 

 were found which are in all probability temnospondylus, and the peculiarity 

 must await future explanation. 



The upper end of the spine is fiattened from side to side and is somewhat 

 spatulate in form. The deep reticulate rugosities cover the upper end and 

 extend down upon the sides to a point a little below the middle of the spine, 

 becoming narrower below and terminating in a blunt point. The anterior 

 and posterior edges of the spine and the spaces below the rugosities are 

 smooth. The second specimen, the apex of a spine, is expanded after the 

 manner of Zatrachys apicalis and is rugose on the top only. 



Length from base of thetransverse process to the top of the spine 86.5 mm. 



No. 3404 (fig. 41 , a and h) is a single dorsal plate from the apex of a spine of 

 a small amphibian. This resembles the plates from the dorsal region of Cacops 

 aspidephorous Williston, in general form, but was free from the spine, as in the 

 Dissorophidse. Aspidosaurus has been reported from the Clear Fork beds as 

 low as just west of the Dundee- Archer City road, i.e., the lowest part, but this 

 is the first specimen of the small armored amphibians from the Wichita forma- 

 tion. The upper surface is deeply rugose, with relatively large pits ; one edge, 

 the anterior (?), is free from pits for a short distance, but is marked with fine 

 lines, evidently marking the position of an overlap by the preceding plate. 

 The lower surface shows very slight projections in the middle portion, as if 

 the plate were loosely attached by cartilage to the apex of the spine below. 



