■26 



PISCES 



CLASS I 



Bavaria, and N. gracilis, Davis, by a smaller skeleton from the Upper Cretaceous 



of Sahel Alma, Mount Lebanon. Detached teeth from 

 the Oxford Clay of England and Corallian of Wurtem- 

 berg; from the Chalk of England (N. microdon, Ag.) 

 and the Cretaceous of New Zealand (N. dentatus, Sm. 

 Woodw.) ; and numerous species from Tertiary forma- 

 tions (e.g. N. primigenius, Ag., Fig. 45). 



Chlamydoselache, Garman. Teeth with broad, back- 



wardly extended base, and the crown consisting of three 



slender, curved, subconical cusps, which are separated 



by a pair of rudimentary denticles. Wide distribution 



Isolated teeth in Pliocene of Tuscany (C. lawleyi, 



Fig. 45. 



Notidanus primigenius, Ag 



Lower tooth. Oligocene 

 Weinheim, Hesse Darmstadt 



Natural size. 



in existing deep sea. 

 Davis). 



Sub-Order B. CYCLOSPONDYLL Hasse. 



Vertebral centra in form of simple constricted cylinders pierced by the notochord. 



Teeth numerous^ triangular, and acuminate, simple or with small lateral cusps. Bare 

 in the fossil state ; Upper Cretaceous to Recent. 



Family 1. Spinacidae. Midler and Henle. Spiny dog-fishes. 



Body fusiform to trihedral, somewl tat depressed. Mouth gently arched; snout 

 obtuse. Gill clefts small, lateral ; spiracles large, behind the eye. Pectoral fins not 

 notched at their origin and not produced forwards ; the two dorsal fins often armed 

 with a spine ; anal fin absent. ' Upper Cretaceous to Recent. 



Centrophorus, Midler and Henle (Fig. 46). Dorsal fin spines present. 

 Upper teeth erect, triangular, or narrow lanceolate, with a single cusp ; lower 



teeth triangular 

 and compressed, 

 with the apex 

 much turned aside. 

 Upper Cretaceous, 

 Sahel Alma, Mount 

 Lebanon (Spinax 

 primaevus, Pictet). 

 Recent. 



Acanthias, Risso 



(Centrophoroides, Davis), (Fig. 47). As Centrophorus, but teeth in upper jaw 

 as in lower jaw. Upper Cretaceous, Sahel Alma, Mount Lebanon (Centro- 

 phoroides latidens, Davis). Tertiary (A. radicans, Probst) and Recent. 

 ( 'entrina, Cuv. Pliocene and Recent. 



Scymnus, Cuv. (Fig. 48). Xo dorsal fin spines. Upper teeth small, 

 pointed ; lower teeth much larger, broad and compressed, triangular, erect or 

 only slightly inclined laterally. Eocene to Recent. 



Echinorhinus, Blainv. (Goniodus, Ag.) Pliocene and Recent. 



Grundlage des Banes und der Entwickehmg ihrer Wirbelsaule. Jena, 1879, with Appendix, 1885. 

 —Miiller, J., and Henle, J., Systematische Beschreibung der Plagiostomen. Berlin, 1841. — Jaekel, 

 0., Die eocanen Selachier vom Monte Bolca. Berlin, 1894. — Noetling, F., Die Fauna des samlan- 

 dischen Tertiars (Abhandl. geol. Specialk. Preussen, vol. VI. pt. 3), 1885. — Probst. Beitrage zur 

 Kenntniss der fossilen Fisclie aus der Molasse von Baltringen (Wurttemb. natnrw. Jahresh.), 1874, 

 1877. 187S, and 1882. 



Fig. 46. 



Vertebra (central double-cone) 

 of Centrophorus. Upper Cre- 

 taceous; Maastricht (after 



Hasse). 



Fig. 47. 



Acanthias roAicans, 

 Probst. Tooth, x 2. 

 Miocene (Molasse) ; 

 Baltringen, Wiirtem- 

 berg (after Probst.) 



Fig. 48. 



Scymn its triangulus, 

 Probst. Tooth, x 2. 

 Miocene (Molasse) ; 

 Baltringen (after 

 Probst.) ^ 



