Revieics — J. W. Davis — Scandinavian Cretaceous Fish. 81 



between the Catalogue just cited and the memoir now before us 

 consists in the fact that the former atteuipts to treat the fossils as 

 remains of genera and species of Elasmobranchs, while the latter 

 deals with them as so many " forms " of detached teeth, which can 

 be distinguished and thus variously named. 



Among featui'es of special interest relating to the Elasmobranchs, 

 may be noted the occurrence in the Danian of typical examples of 

 Ptycliodus decurrens, P. mammiUaris, Notidanus microdon, Oxyrliina 

 ManteUi, and the so-called Otodus appendictdatus — all well-known 

 Cretaceous forms. With these are found an undetermined species 

 of Myliobatis, and some apparently new forms of Scapanorliynclius, 

 Oxyrliina, Lamna, and Scyllium, besides a large imperfect tooth of 

 Notidanus indistinguishable from TV. dentntus of the New Zealand 

 Greensand. An Odontaspis, both from the Senonian and Danian, is 

 also identified with a New Zealand species (0. acuta) ; but we 

 venture to think that this is the well-known European Danian 

 species, 0. Bronni, to which the author makes no reference. The 

 so-called Odontaspis acntissima and 0. faxensis are undoubtedly teeth 

 of Synechodns, as proved by the form of the root ; and, as remarked 

 by the author himself, there is much doubt about the generic deter- 

 mination of the beautiful new teeth described as Oxyrliina Lundgreni. 

 Tliough often recorded from the Cretaceous, it is still very uncertain 

 whether the typically Tertiary species, Odontaspis elegans, ranges 

 so far downwards, and the smooth teeth assigned to this form by 

 Mr. Davis are far from conforming to Agassiz' original definition ; 

 but the occurrence of a tooth indistinguishable from the so-called 

 Otodus obliquiis in the Upper Senonian of Rugaard is a fact of great 

 interest. A portion of a tooth of Carchnrodon from the Danian 

 of Faxoe is even identical in character with the teeth of the existing 

 C. RondeJeti, but this scarcely suffices for certain determination. 



Some Chimaeroid teeth from the Senonian appear to pertain to the 

 widely distributed species, first described from Switzerland as 

 Ischyodus Tliurmanni and afterwards re-described in Bi'itain under 

 the name of Ischyodus brevirostris. P^dapliodon, however, remains 

 unknown, and there are no traces of Elasmodus. 



Of Pycnodonts, there occur only teeth which are referred with 

 much probability to Coelodus subclavatus ; and of Teleosteans there is 

 only evidence of about six genera. Of the latter, the finest specimens 

 pertain to Hoplopteryx and to a new deep-bodied physoclystous fish, 

 which receives the name of Bathysoma Lutheni. Berycopsis and 

 Dercetis also seem to be represented ; another fossil is provisionally 

 named Clupea Lundgreni ; and some specifically indeterminable 

 teeth of Encliodiis are recorded. With regard to Encliodus we would 

 remark that the author does not seem to have studied the most recent 

 discoveries, and thus assigns the genus still to the family Trichiurid^. 

 Here is also placed Bathysoma, though a critic noting the fact will 

 perhaps be answered again in the words of the foot-note on p. 369, 

 that the arrangement is due to " the omission of a line." Bathysoma, 

 indeed, is one of the most remarkable Cretaceous fishes hitherto 

 discovered, and we only regret that a more satisfactory determination 



DECADE III. VOL. VIII. NO. II. 6 



