Dr. R. H. Traquair — On CycIoptycMus carbonarius. 245 



come to the tail, when they become very small, and acutely lozenge- 

 shaped on the prolongation of the body along the upper caudal lobe. 

 The scales of the back and belly are smaller than those of the sides ; 

 azjfgos, somewhat heart-shaped scales are often seen in the mesial 

 dorsal line, where the oblique rows of each side meet ; but I do not 

 see any specially large ones in front of the dorsal and anal fins, as in 

 FalcBoniscus. The upper aspect of the caudal body prolongation is, 

 however, bordered, as in all the members of this family, by a series 

 of V-shaped scales ; whether or not these become a double series by 

 the complete splitting of the legs of the V, is not seen. The lateral 

 line, marking the course of the lateral slime-canal, is very distinctly 

 traceable from the 2nd supra-clavicular along the middle of the side 

 of the body to the origin of the lower lobe of the caudal fin ; the 

 scales which it traverses being each marked with a slight ridge or 

 elevation, which disturbs very considerably the regularity of the 

 proper strige of the scale. 



Fins. — The pectorals and ventrals are very small, and have ap- 

 parently rounded terminations ; the ventrals, each having about 2C 

 delicate rays, are placed nearly midway between the pectorals and 

 the anal. The dorsal is placed very far back, being quite opposite 

 the anal, which it resembles both in size and shape ; both are trian- 

 gular and pointed, with the posterior margin rather concave. To 

 count the fin-rays in such delicate little fossil fishes is rather a 

 difficult and uncertain matter ; but I would estimate the number in 

 the dorsal and anal fins at about 30 for each, of which the posterior 

 10 are very fine. They do not bifurcate till near their terminations ; 

 their transverse articulations are rather distant, especially near the 

 attachment of the fin : minute fulcral scales, rather thinly set, may 

 be seen along the anterior margins. The caudal is deeply bifurcated ; 

 both lobes are pointed ; the upper one is bordered above by the 

 scaled body-prolongation, and projects rather further back than the 

 lower. The fulcral scales along the margin of the lower lobe are 

 more distinct and closely set than those of the dorsal and anal fins. 

 About 18 or 19 rays go to form the lower lobe ; the rest become 

 exceedingly fine and delicate as we proceed on towards the tip of the 

 upper lobe. 



Internal skeleton. — In none of the specimens I have examined is 

 there any trace of internal skeleton in the trunk. The fish was 

 evidently notochordal. 



Conclusion. — The entire structure and aspect of CycloptycMus car- 

 bonarius prove it to be a member of the same extinct family of 

 Lepidosteoid Ganoids to which Falceoniscus, Pygopterus, Oxygnathus, 

 etc., belong. Dr. Young has already correctly recognized its affinity 

 to Falceoniscus ; but I cannot agree with him in assigning to it any 

 special relationship to the Catopterus of J. H. Redfield, as the latter 

 genus is imperfectly heterocercal, and therefore can hardly be in- 

 cluded in the family of Palseoniscidse, any more than the genus 

 Ischypterus of Egerton.' 



1 See the description and figure of Catopterus, by "W. H. Redfield, Ann. Lyceum Nat. 

 Hist. New York, iv. p. 38, pi. i. ; and by J . C. Redfield, Am. Journ. Sc. 1841, xli. 

 p. 27. 



