higher plectognath category appeared in his (1866) "On 

 the Anatomy of Vertebrates." In the latter work, the 

 Order Plectognathi was composed of two sub- 

 orders: Sclerodermi, with the family Balistini; and 

 Apleuri, with the families Ostraciontidae and Gym- 

 nodontidae. 



This is not the place to discuss the histological struc- 

 ture and composition of the plectognath teeth and scales, 

 nor to attempt to summarize the highly conflicting infor- 

 mation available. But since some recent workers are not 

 aware of all the older literature dealing with this sub- 

 ject, it is useful to list the more important references to 

 the histology of the scales and teeth of plectog- 

 naths: Bom 1827 (teeth of gymnodonts). Owen 1839 

 (teeth of Tetraodon and Diodon); 1840 & 1845 (teeth of 

 Balistes, Tetraodon, and Diodon). Williamson 1851 

 (scales of Balistes and Ostracion). Hollard 1857a 

 (scales of Ostracion). Cleland 1862 (bony tubercles in 

 skin of Mola). Turner 1862 (bony tubercles in skin of 

 Mola). Hertwig 1881 (scales of numerous plectog- 

 naths, mostly gross morphology, but some his- 

 tology). Hilgendorf 1886 (mostly gross morphology of 

 teeth of Tetraodon and Diodon); 1893 (teeth of Mola, 

 Tetraodon, and Diodon). Wortman 1886 (teeth of 

 Balistes and Diodon). Green 1901 (subdermal tissue of 

 Mola). Green and Tower 1902 (albuminoids in scales of 

 Mola and Sphoeroides) . Ghigi 1905a, 1905b (teeth of 

 Balistes); 1921 (teeth of Ostracion and 

 Tetraodon). Rosen 1913 (scales of numerous plectog- 

 naths); 1916b (scales of plectognaths in comparison 

 with those of other fishes). Kaschkaroff 1914a (scales of 

 numerous plectognaths). Rauther 1919, 1927a (scales of 

 Balistes); 1927b (teeth of numerous plectognaths). 

 Tretjakoff 1924a, b, 1926a, b (scales of numerous 

 plectognaths); 1925 (pectoral fin rays of Tetraodon com- 

 pared with body scales); 1926c (teeth of numerous plec- 

 tognaths). Pflugfelder 1930 (teeth of Tetraodon and 

 Diodon in particular, but also of Ostracion and 

 Balistes). Grieb 1935 (pharyngeal teeth of 

 Sphoeroides). Arsuffi 1939 (teeth of Tetraodon). Bar- 

 tolini 1941 (general discussion of plectognath 

 teeth). Isokawa 1955 (teeth of Monacanthus and 

 Cantherhines). Soule 1969a, b, 1970 (tooth attach- 

 ment in balistids). More recently Roberto Andreucci 

 and his colleagues in Brazil have begun a systematic 

 reexamination of the histology of plectognath teeth (so 

 far confined to gymnodonts): Andreucci 1966a, b, 

 1967a, b, 1968a, b, 1969, 1970; Andreucci and 

 Britski 1968a, b, 1969a, b, 1970, 1971; Britski and 

 Andreucci 1971; Andreucci and Blumen 1971. 



A landmark in the study of almost all groups of fishes 

 was the publication of Gunther's "Catalogue of the Fishes 

 in the British Museum." Here was a consistent, stan- 

 darized description of nearly every order, family, genus, 

 and species of known fishes. The Plectognathi appeared 

 in volume 8, published in 1870. In the subclass Teleostei, 

 six orders were recognized: Acanthopterygii, 

 Acanthopterygii Pharyngognathi, Anacanthini, 

 Physostomi, Lophobranchii, and Plectognathi. The plec- 

 tognaths were divided as follows: 



Order Plectognathi 

 Family Sclerodermi 



First Group: Triacanthina 



Triacanthodes, Hollardia, Triacanthus 



Second Group: Balistina 



Balistes (with six subgenera: Liurus, Balistes, 

 Canthidermis, Parabalistes, Melanichthys, Ery- 

 throdon), Monacanthus (with two subgenera: 

 Monacanthus and Aluteres), Anacanthus 



Third Group: Ostraciontina 



Ostracion (with two subgenera: Ostracion and 

 Aracana) 

 Family Gymnodontes 



First Group: Triodontina 

 TYiodon 



Second Group: Tetrodontina 

 Xenopterus, Tetrodon (with 10 subgenera: Tetro- 

 don, Hemiconiatus, Gastrophysus, Cheilichthys, 

 Liosaccus, Crayracion, Chelonodon, Monotretus, 

 Arothron, Anosmius), Diodon, Chilomycterus, 

 Dicotylichthys, Atopomycterus, Trichodiodon, 

 Trichocyclus 



Third Group: Molina 



Orthagoriscus (with two subgenera: Orthagoriscus 

 and Ranzania). 



The classification of the Plectognathi followed by 

 Gunther (1880) in his "An Introduction to the Study of 

 Fishes" was essentially the same as that given above. 



There was nothing special about Gunther's (1870) treat- 

 ment of the Plectognathi, and it could be held to be dis- 

 tinctly inferior to that given 4 years earlier by Bleeker 

 (1866). Gunther's most notable failure was his handling of 

 the admittedly difficult "Tetrodontina." The tetraodon- 

 tids are a far larger and more diversified group than the 

 diodontids, yet Gunther recognized only two genera of the 

 former (albeit with 10 subgenera, but these were based 

 primarily on the form of the nostril, an unreliable charac- 

 ter when used alone rather than in conjunction with a 

 number of other anatomical systems) but six genera of 

 the latter (defined by the form of the nasal tentacle and 

 the movability of the spines). 



In his (1871a) "Observations on the Systematic 

 Relations of the Fishes," Cope, while giving credit to 

 Muller as (p. 580) "the father of modern ichthyology," 

 nevertheless thought that within the teleosts the Plectog- 

 nathi and Lophobranchii were not of equal rank with 

 the Physostomi and Physoclisti. Thus, within the Sub- 

 class Actinopteri (= Muller's Teleostei and Ganoidei), 

 Cope recognized three tribes: the Chondrostei ( = 

 Mailer's Order Chondrostei of the Subclass Ganoidei), 

 Physostomi, and Physoclisti. The Physoclisti contained 

 10 orders, including the Plectognathi. Cope stated 

 (1871a:582) that phylogenetic lines radiate out from the 

 Percomorphi and that "one leads from the Chaetodon- 

 tidae, through the Acroneuridae [= Acanthuridae], to 

 the Plectognathi, by the similarity in the arrangement of 



