PAL^ONISCTTS, GYROLEPIS, AND PYGOPTERIJS. 559 



Traquair). I had long suspected that a very beautiful species from 

 Burdiehouse was identical with the P. ornatissimus, Agassiz ; and a 

 few days ago I obtained two of the original specimens of that species, 

 and found that one of them, at least, certainly confirmed my opinion. 

 It is the type of a group including P. carinatus, Ag., a species de- 

 scribed from a very imperfect specimen from the Wardie shales now 

 in the museum of the Royal Society of Edinburgh. Examples in a 

 much better state of preservation, however, have subsequently turned 

 up in the same locality. The body is slender, elegantly shaped ; the 

 scales are rather large, especially on the Hank ; the median fins are 

 large in proportion to the size of the fish ; the dorsal is situated 

 nearly opposite the anal ; the caudal body -prolongation is delicate. 

 I have had no satisfactory view of the dentition or of the structure 

 of the pectoral fin in this species ; but its general aspect leads me to 

 class it along with the Palceoniscus ornatissimus, Ag., and Palceoniscus 

 Wardii, of Prof. Young, recently briefly described by Mr. Ward, 

 of Longton *, as constituting a new genus, Rhadinichthys. The 

 characters of generic importance displayed by the two last named 

 species are as follows : — The body is comparatively slender ; the 

 suspensorium is very oblique ; the jaws are armed with a row of 

 incurved conical laniaries, outside which there is a series of smaller 

 teeth ; the principal rays of the pectoral fin are, as in Pygopterus 

 and Oxygnathus, unarticulated till towards their terminations ; the 

 dorsal is situated rather far back, nearly opposite the anal ; the 

 caudal body-prolongation is comparatively delicate. There are, 

 besides these, several other new species from British Carboniferous 

 strata referable to this type, the description of which I hope soon to 

 be able to overtake ; in some of these the scales are nearly smooth, 

 as in R. carinatus, in others elaborately ornamented. 



Pabvoniscus Albertii, of Jackson, seems to me to be allied to R. 

 carinatus ; but more especially so, judging from the drawings, is his 

 P. Caimsii, and some of the other small Palaeoniscidao from the 

 Coal Measures of New Brunswick, figured, but not described, by the 

 same author f. All the species which I propose to include under 

 Rhadinichthys are from Carboniferous strata. 



The three remaining types included by Agassiz in Palceoniscus 

 must be altogether excluded from the family Palaeoniscidae. 



V. Type of Palceoniscus fultus, Ag. (Genus Ischypterus, Egerton). 

 This Triassic species, in which the caudal body-prolongation is con- 

 siderably more reduced than in the Pakeoniscidoe, the tail con- 

 sequently showing the first approach to the semiheterocercal form, 

 and whose general structure, including the osteology of the head, 

 betrays a strong affinity to Semionotus, has been already separated 

 by Sir Philip Grey- Egerton under the name of Ischypterus %. 

 Besides Ischypterus fultus, Ag., sp., there are here included /. 

 Agassizii, I. macropterus, I. latus (= Eurynotus Unuiceps, Ag.), and 



* North Staffordshire Naturalists' Field Club, Addresses and Papers 

 (Hanley, 1875), pp. 239-240. 



t Keport on the Albert Coal Mine, New Brunswick. 



J Quart. Journ. Geol. Soc. iii. 1847, p. 279; ibid. vi. 1850. p. 8. 



