Geological Society, 161 



and such a parallelism of successive surfaces of dry land, ought to 

 be expected, according to the theory of repeated subsidence, be- 

 cause sedimentary deposition would continually exert its leveling 

 action on the district submerged. 



May 10. — A paper was read "On some new Ganoid Fishes." By 

 Sir Philip Grey Egerton, M.P., F.G.S. 



The specific characters of the fishes described are as follows : — 



1. Semionotus Pentlandi, Egerton. — Body deep; pedicle of the tail 

 thicker proportionally than in Semionotus latus. Anal fin long, with 

 5 or 6 rays, articulated, subdivided, and decreasing in length from 

 the first. Bases distant ; 3 or 4 fulcral rays on the margin. Caudal 

 fin large ; upper lobe invested with scales for some distance. Mar- 

 gins fringed by elongated imbricated scales. Rays : 20, articulated, 

 subdivided. Bases at greater intervals near the centre. Scales 

 rhomboidal, smooth, with entire margins. Stratum, Lias. 



Found by Mr. Pentland in a black bituminous schist at GifFoni, 

 near Castella Mare. In the cabinets of the Earl of Enniskillen and 

 Sir Philip Egerton. 



Of the six species of Semionotus described by Professor Agassiz, 

 one is from the quader-sandstein, the other five from the lias of 

 Lufeld, Boll, Lyme Regis, and Schoven in Sweden. From a com- 

 parison of Mr. Pentland's specimens of this and the two following 

 species with all those described. Sir Philip Egerton considers they 

 approximate more nearly the species of the lias than those of the 

 greensand, and infers from this zoological evidence that the GifFoni 

 beds belong to the former. 



2. Semionotus jmstulifei^Egertori. — Fish large; operculum arenated; 

 humerus and scapula pustulated ; scales thick and lustrous ; surfaces 

 slightly uneven ; upper and lower margins deeply undulate. Stratum, 

 Lias ; found with last. Cab. Egerton. 



3. Semionotus minutus, Egerton. — Fish small ; body slender ; cau- 

 dal pedicle thick ; scales extended over the upper lobe of the tail. 

 Stratum, Lias ; found with last. Cab. Egerton. 



4. Lepidotus pectinatus, Egevton. — Fish oblong, subfusiform; length 

 9 inches ; depth 2| ; head small ; fins small ; scales marked with 

 delicate radiating striae ; posterior margin finely pectinate ; upper 

 edge convex, lower one concave ; dorsal, anal and caudal scales 

 rhomboidal, with entire margins. Stratum, Lias. Locality, Whitby. 

 Cab. Enniskillen. 



5. Pholidophorus Hartmanni, Egerton. — Size of Pholidophorus 

 latiusculus. Head rounded ; orbit large ; upper angle of operculum 

 striated ; preoperculum marked with few moniliform inequalities ; 

 humerus plicated ; scales small, serrated on the posterior margin ; 

 its serrations decrease in number and increase in size on the pos- 

 terior parts of the body. Stratum, Lias. Locality, Ohmden, in Wur- 

 temburg. Cab. Enniskillen, Egerton. 



6. Pholidophorus crenulatus, Egerton. — Rather larger than Pho- 

 lidophorus latiusculus. Head rather pointed ; humerus obliquely 

 plaited ; pectoral fins large, with 22 rays ; caudal fins strong ; the 

 upper lobe bordered full two-thirds of its length with fulcral scales ; 



