THE OSTEOLOGY AND IMMEDIATE RELATIONS OF THE TILE-FISH, 

 LOPHOLATILUS CHA1VLELEONTICEPS. 



By FREDERIC A. LUCAS, 



Curator, Division of Comparative . Inalomy, 

 U.S. National Museum. 



The genera Latilus, CaulolatUus, Lophoiatilus, and Malacanthus have usually 

 been grouped in one family, the Malacanthidae, but Bouleuger" adds to these 

 Opisthoynathus, Bathyraast, •»•, and Ratldiunella to form his Pseudochromidfe. It 

 was suggested by Doctor Jordan, in The Fishes of North and Middle America, that 

 the family Malacanthidae might not be a natural assemblage, and the present paper 

 is an attempt to define its limits; the question of affinities with other species or fam- 

 ilies must await the accumulation of more material. 



The skull of Lophoiatilus is moderately elevated, with an occipital crest formed 

 almost entirely by the supraoccipital, which extends forward between the frontals 

 and is produced backward as a narrow tongue of bone running between the exoccipi- 

 tals to the foramen magnum. In Malacanthus the supraoccipital is not extended 

 forward between the frontals, nor is it produced backward between the exoccipitals, 

 these bones interposing between the supraoccipital and the. foramen magnum. 



The mesethmoid extends well forward, slightly in advance of the vomer, and is 

 deeply forked, while in Malacanthus there is a mere indication of a fork. The 

 vomer is proportionately broader in Lophoiatilus, as is also the parasphenoid, the 

 anterior forks of which do not reach so far forward. At the same time the keeling of 

 the parasphenoid in Lophoiatilus is ^-shaped in cross section, while in Malacanthus 

 in the anterior part it is decidedly i-shaped. In the particular characters mentioned, 

 as in the general arrangement of the bones of the cranium and their relations with 

 each other, Latilus and Caidolatilus agree with Lophoiatilus and disagree with Mala- 

 canthus. A myodome is present in all these genera. 



The number of vertebra?, not including the terminal semivertebra, is approxi- 

 mately the same in all the species under consideration, being in Lophoiatilus In 

 thoracic and 13 caudal, in Latilus 11 and 12, in Caulolatilus 12 and 14, and in 

 Malacanthus 10 and 13. In Malacanthus the vertebra? are somewhat elongate and 

 but lightly sculptured on the sides, while the other genera agree in having the 

 vertebra? not elongated and rather deeply sculptured. 



"Annals and Magazine of Natural History, 7th series, vol. 8, i». 270. In the same paper (p. 2t>4) Bouleuger gives 

 excellent figures illustrative of the principal characters of the shoulder girdle of C'aulolatilm and two of the genera with 

 which the latilids have been associated. 



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