436 On some Ganoid Fishes from the English Loicer Lias. 



upper half of the principal caudal fin (c), these rays being 

 articulated, though not expanded, distally ; and there are 

 remains of a well-developed supplementary caudal fin (sc). 

 The squamation is only preserved in the anterior half of the 

 abdominal region and at the base of the supplementary caudal 

 fin, each scale being ornamented with four to six large elon- 

 gated tubercles, irregularly arranged in an antero-posterior 

 direction, and sometimes subdivided transversely (fig. 5 a). 



Determination. — The fish thus described is closely similar 

 in proportions and in the character of its fin-rays to the 

 typical Coelacanthus ; but it is generically distinguished by 

 the presence of denticles upon the first dorsal fin and by the 

 scale-ornament. With the Jurassic genus Undina*, how- 

 ever, it agrees in every essential particular except the non- 

 expansion and comparatively sparse articulation of the distal 

 half of the fin-rays ; and as these characters are of doubtful 

 value, it seems advisable, at least provisionally, to place the 

 Barrow species in the well-known genus just mentioned. To 

 the present writer it appears that no sufficient generic differ- 

 ence has yet been pointed out between the so-called tlolo- 

 j>hagus and Undina • but the new fossil now described is 

 distinguished both from the Lyme Regis fish and the typical 

 species of the Bavarian Lithographic Stone by the characters 

 of the fin-rays and scales and by the comparative fewness of 

 the caudal fin-rays. The specimen may thus be regarded as 

 indicating a hitherto unknown species, for which the name of 

 Undina barroviensis will be appropriate. 



EXPLANATION OF PLATE XVI. 



Fig. 1. Centrolepis asper, Egerton. Scales of flank, twice nat. size. 

 Lower Lias, Lyme Regis. [B. M., no. P. 5594.] 



Fir/. 2. Coccolepis Uassicus, sp. nov. Lateral aspect of fish. Ibid. [B. M., 

 no. P. 887.] 



Fig. 3. Ditto. Head, lateral aspect, twice nat. size. Ibid. [B. M., no. 

 P. 6153.] br., branchiostegal rays; md., mandible ; ?».*., 

 maxilla; orb., orbit; op., operculum; pet., pectoral fin. 



Fig. 4. Ditto. Caudal region, lateral aspect. Ibid. [B. M., no. 39865.] 



Fig. 4 a. Scale of ditto, three times nat. size. 



Fig. 5. Undina barroviensis, sp. nov. Lateral aspect of fish. Lower 

 Lias, Barrow-on-Soar. [B. M., nos. 21335, P. 3343.] c, prin- 

 cipal caudal tin ; d x , d 2 , first and second dorsal fins ; ju., jugular 

 plate ; ptq., pterygo-quadrate bone ; sc, supplementary caudal 

 fin ; x, parafrontal (? or sclerotic) plates. 



Fig. 5 a. Scales of ditto, three times nat. size. 



[B. M.=British Museum. Unless otherwise stated the figures are of the 



natural size.] 



* G. von Minister, Neues Jahrb. 1834, p. 539, and Beitr. Petrefakt. 

 pt. v. (1842), p. 57. 



