28 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



structure of the caudal and other tins. The dorsal and anal are situated oppo- 

 site each other, and consist each of 20 rays. The caudal is short and much 

 expanded, covered with a scaly lamella along the middle at its base, and the 

 distance between the extremities of its lobes exceeds the maximum depth of 

 the trunk. All of the tins have the foremost ray covered with a finely rugose 

 dermal layer, and the anterior pectoral fin-ray is as much enlarged and elon- 

 gated as in certain Osteoglossidae and Chirocentridae. This species, of which 

 several examples are known, attains a total length of about 80 cm. 



SCOPELIDAE. 



Holosteus esocinus Agassiz. 



1838-44. Holosteus esocinus L. Agassiz, Poiss. Foss., v. pt. 2, p. 85, Plate XLIII. 



Fig. 5. 

 1856. Holosteus esocinus H. G. Bronn, Lethaea Geognostica, p. 683, Plate XLII.^ 



Fig. 8. 

 1874. Holosteus esocinus A. de Zigno, Catalogo ragionato del Pesci Fossili, p. 140. 



The holotype and only known example of this species is an imperfectly 

 preserved fish belonging to the G-azola Collection of the Paris Museum. It 

 bears on the reverse the following MS. inscription in Agassiz's handwriting ; 

 " Cette plaque est evidemment composee de pieces incoherentes, surtout de la 

 partie anterieure de la dorsale, et vers le front de la tete; cependant la colonne 

 vertebrale indique un poisson d'un genre nouveau voisin de Belone." 



An examination of the specimen shows that the vertebral column is intact 

 from the occiput at least as far as the insertion of the dorsal fin, the latter 

 being unquestionably preserved in its natural position. It is evident that the 

 triangular piece intended to represent the interneurals supporting the dorsal 

 does not belong to this fish, and the same remark applies also to another 

 fragment introduced in advance of the dorsal, which was properly recognized 

 by Agassiz as " n'etant q'une fausse dorsale." Although the authenticity of 

 the anal itself is doubtful, its position is shown by the presence of fin-supports 

 to be opposite the dorsal. Very little of the portion posterior to the anal fin 

 can be regarded as other than a factitious mosaic. 



CAEANGIDAE. 

 Caranx primaevus, sp. nov. 



(Plate 1, Fig. 4 ; Text-fig. B.) 



A small species attaining a total length of about 10 cm. Head with oper- 

 cular apparatus contained slightly less than 3^ times in the total length to base 

 of caudal fin. Trunk laterally compressed, elongated, regularly fusiform. An- 



