Vol. 5] 



Jordan. — The Fossil Fishes of California. 



99 



loped. There are distinct perforations between the ridges of the 

 serrated base. Directly in front of the first of the cluster of three 

 lateral denticles there is a depression in the contour of the tooth 

 corresponding with the depression in front of the first denticle on 

 the opposite side of the cone. ' ' 



A second tooth, very small, No. 10,196, is much like the type 

 of Hybodus shastensis, but the main cusp is much lower, and 

 there are no lateral cusps. This is also from Bear Cove, and prob- 

 ably belongs to the same species. 



A third tooth, still smaller, and doubtless from the outer edge 

 of the jaw, has the median cusp reduced to a rounded, striated 

 prominence ; the other cusps not developed. 



Still another specimen (No. 1,068), received later, seems also 

 to belong to Hybodus shastensis. The general form is similar, 

 but the base of the crown has a slightly reentrant angle or eon- 

 cavity when it meets the root. Two smaller cusps are evident on 

 one side of the base ; the other side is broken. 



A part of a fin-spine (10,193) is also preserved from the 

 same region. It is smooth in outline, finely striated and rapidly 

 tapering upward. On the same piece of rock is a fragment of a 

 scale of Holoptych us. 



Besides these teeth are numerous tubercles probably belong- 

 ing to the same species of Hyboelus. On one specimen (No. 

 10,204), from "Camp Wemple, " there is a series of rounded, 

 bluntly conical tubercles coarsely striated. There are about eight- 

 een of these in a lengthwise series of nearly two inches, and three 

 or four in a crosswise series of nearly half an inch. These may 

 be part of the rough shagreen of the skin of the shark Hybodus. 

 Similar but larger tiubereles are figured by Woodward from the 

 head of Hyboelus elelabeehei. Another specimen contains a series 

 of five rounded, blunt, equal tubercles arranged in a regular 

 series. This may be from the posterior edge of a fin-spine. This 

 is from Bear Cove (No. 10,195). Still another, about y 2 X Vk, is 

 evenly covered with small, close set, very blunt, smooth tubercles. 

 This is No. 10,192, from Brushy Slope. It may be a fragment of 

 shagreen. The fact that its outline is rounded and that the me- 

 dian tubercles are largest renders this uncertain. One tubercle is 

 1-3 inch in diameter, six-angled, with a. median pit. This looks 

 like a buckler from the back of a ray. 



