130 NEW YORK STATE MUSEUM 



dorsolateral in some other coccosteids, for instance C. m i n o r 

 and C . m a g n u s . 



Neither of the posterior dorsolaterals is preserved. 



Lateral plates. A lateral (L) and an interlateral (IL), both 

 apparently belonging to the same side of the animal, are preserved. 

 They are of the form usual in Coccosteids. They seem to be dis- 

 tmct plates and not, as might be expected by analogy with Dinichthys, 

 the halves of a single plate. ^ 



Ventral armor. The ventral plates are shifted from their 

 natural positions and incompletely preserved. The antero-ventro- 

 lateral (AVL^) of the left side is preserved in outer aspect. It is 

 relatively broad and characterized by the presence of a lateral line 

 on its anterior third. The ornamentation on this plate is w^ell pre- 

 served; it consists of small, blunt, conical tubercles vv^ith fine radi- 

 ations at their bases. 



The right postero-ventrolateral (PVL) is seen from the inner 

 side; it is of the form usual in Coccosteus. 



The median ventral (MV) is only partly preserved — in outer 

 ornamented aspect. Its over-lapped flanges seem broader than com- 

 mon in Coccosteus — probably an adaptation for strengthening the 

 ventral armor. 



Notochordal region. This is shown here for the first time 

 in an American coccosteid. Immediately behind the dorsomedian 

 plate there is a group of neural spines and dorsal fin-rays, repre- 

 sented by their actual tissue. Back of these, extending a distance of 

 13 centimeters, to the end of the slab, there is a double series of 

 impressions arranged in a gently sigmoid line. These correspond to 

 neural and hemal arches and indicate the position of the noto- 

 chord (N). Impressions of some neural spines are also clearly 

 shown. 



About 4 centimeters back of the dorsomedian there is a sickle- 

 shaped rod (p.f) terminating posteriorly in what seems to be a 

 broad plate, though this is either buried in the matrix or missing. 

 This element I identify as one of the so-called " pelvic fin " supports, 

 recently discussed in detail by Professor Dean.- 



1 A discussion of these elements has recently been given by Burnett Smith. 

 \ Notes on Some Little-known Fishes from the New York Devonian. Proc. 

 Acad. Nat. Sciences Phila., Dec. 1910, p. 656-63. 



'^ Bash ford Dean. Studies on Fossil Fishes (Sharks, Chimoeroids, and 

 Arthrodires). Mem. Amer. Mus. Nat. Hist., IX, 1909, p. 282. 



