OCR Text |
Show 1890.J ON SOME UPPER CRETACEOUS FISHES. 629 EXPLANATION OF PLATE LIII. Fig. 1. Diplothele walshi, p. 622. la, Spider in profile, without legs; 1 b, sternum and labium; 1 c, eyes from above and behind; 1 d, extremity of falx ; 1 e, tarsus of leg of 1st pair ; 1/, hinder part of abdomen, and spinners in profile; 1 g, ditto from below; 1 h, one of the maxillce. 2. Dendricon rastratum, p. 623. 2 a, cephalothorax in profile, without legs; 2 b, eyes from above and behind; 2 c, spinners from below. 3. Migas paradoxus, p. 624. Nest. 4. Platyoides abrahami, p. 625. 4 a, underside, showing maxillre, labium, and sternum; 4 b, eyes from above and behind; 4 c, Spider in profile, without legs; 4 d, extremity of tarsus of 3rd pair of legs ; 4 e, spinners from below ; 4/, genital aperture; 4g, lengths of the four legs. 5. Robsonia formidabilis, p. 625. 5 a, eyes from above and behind ; 5 b, Spider in profile, without legs; 5 c, right palpus from outer side ; 5 d, lengths of two examples. 6. Argyroepeira blanda, p. 627. Abdomen, upperside. 6 a, ditto in profile. 7. letragnatha taylori, p. 627. One of the falces. 8. Cosrostris albiceps, p. 628. 3. On some Upper Cretaceous Fishes of the Family of Aspidorhynchidce. By A. S M I T H W O O D W A R D , F.Z.S. of the British Museum (Natural History). [Received November 4, 1890.] (Plates LIV. & LV.) Among the fishes met with in Upper Cretaceous rocks, there are very few representatives of the " ganoid " types so characteristic of earlier Mesozoic formations. Solitary survivors, however, do occur in almost every fish-fauna of late Cretaceous date hitherto discovered ; and conspicuous among these are members of the remarkably specialized family of Aspidorhynchidae. It is of much interest to compare the latest species of such a family with those by which it was represented at earlier periods; and a large series of specimens in the British Museum now enables this comparison to be made in a more satisfactory manner than has hitherto been possible. A number of undescribed fossils from the Upper Cretaceous of Brazil are referable to the genus Belonostomus, and reveal most of the principal external characters of the species they represent; while some fine examples of another genus, as yet imperfectly described and inaccurately determined, prove the occurrence of an allied, though more specialized, fish in the corresponding formation of Mount Lebanon, Syria. Genus BELONOSTOMUS. [L. Agassiz, Poiss. Foss. vol. ii. pt. ii. 1844, p. 140.] BELONOSTOMUS COMPTONI. (Plate LIV., Plate LV. figs. 1-10.) 1841. Aspidorhynchus comptoni, L. Agassiz, Edinb. New Phil. Journ. vol. xxx. p. 83. |