PALAEONTOLOGY 



head turtle which has been named by the writer Thallasochelys eoccenka ; 

 while a fragment of the shell is sufficient to prove the existence at the 

 same epoch of a species belonging to an extinct genus {Psephophorus) 'of 

 leathery turtle.^ 



Vertebrae of two species of large serpents belonging to an extinct 

 family also occur in the Bracklesham beds. One of these, Palaophis 

 toliapicus, is typified by specimens from the London Clay of Sheppey ; 

 but the second, P. typhceus, was described on the evidence of Bracklesham 

 fossils. These snakes, judging from the form of the vertebra, appear 

 to have been marine. 



The list of Bracklesham fishes is considerably larger than that of 

 the reptiles, and includes at least nine species first described from that 

 formation, some of which are peculiar to the same. First on the list 

 come two species of saw-fish, Pristis cojitorttis and P. bisulcatus, the 

 former of which is confined to the Bracklesham beds, while the latter 

 also occurs at Barton, Hants. The flattened roller-like dental plates of 

 eagle-rays are especially common in these deposits, and have been 

 assigned to five species, namely Myliobatis dixoni, M. striatus, M. gonio- 

 pkiirus, M. toliapicus, and M. latidens, the last alone being typified by 

 Bracklesham specimens. There are likewise two species of ray belong- 

 ing to the allied genus Aetobatis, of which A. ftiarginalis is exclusively 

 from Bracklesham, while A. irregularis also occurs in other Eocene 

 deposits, and is typically from the London Clay. 



Among sharks there are three representatives, Odontaspis elegans, 

 O. macrota^ and O. cuspidata, of an extinct genus nearly related to the 

 living porbeagle ; the three species are widely spread, and the first 

 occurs at Newhaven as well as at Bracklesham Bay. There is also an 

 extinct species of porbeagle, namely Lamna vince?iti, not peculiar to the 

 Bracklesham beds, as well as the so-called Otodus obliquus, occurring 

 elsewhere in the county in the Middle Eocene beds of Bognor. Large 

 teeth from Bracklesham have been assigned to Carcharodon auriculatus, 

 a widely-spread extinct relative of the largest of living sharks (C. 

 rondeletii). Another Bracklesham shark is Galeocerdo latidens, a species 

 likewise with a wide geographical distribution. 



Of fish allied to the living chimasra, or ' king of the herrings,' 

 there are two representatives, Edaphodon bucklandi and £. leptognathus, 

 both common to other Tertiary horizons. Fish-spines described as 

 Coelorhynchus rectus are also found in the Bracklesham deposits, from 

 which came the type specimens. Among the pycnodont ganoid fishes, 

 in which the palate and lower jaw are armed with a pavement of 

 spherical or oval crushing teeth, the species Pycnodus kcenigi was first 

 described from Bracklesham, but has been subsequently identified from 

 the corresponding formation of Belgium. 



As ' cat-fishes ' (Siluridc^) are comparatively rare as fossils, it is 



1 Cat. Foss. Rept. Brit. Miis. iii. 224. 



2 For the generic of this and two of the undermentioned species, see A. S. Woodward, Proc. Geol. 

 Assoc, xvi. 10 ; in Cat. Foss. Fish. Brit. Mus. they are assigned to Lamna. 



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