that: Mola is the only plectognath with a skeleton less 

 ossified than that of the majority of fishes (but Cuvier 

 had stated only that the ossification was "tardif," while 

 otherwise like that of other fishes); the premaxillaries 

 and maxillaries are fixed firmly to one another in a num- 

 ber of fishes other than plectognaths; the palatine is 

 movable in certain scleroderms (Cuvier implied that it 

 was sutured to the cranium in all plectognaths); the 

 operculum and branchiostegal rays are hidden beneath 

 the skin in a number of fishes other than plectognaths; 

 Triodon possesses ribs; some scleroderms possess pelvic 

 fins (Cuvier said that they are always absent in plectog- 

 naths); Mola does not have a swim bladder (Cuvier said 

 that it is well developed in all plectognaths). 



Dareste (1850) went too far when he criticized Cuvier 

 for not knowing that Triodon possessed ribs. In the first 

 edition of the "Le Regne Animal," Cuvier (1817) stated 

 that the plectognaths had only very small vestiges of ribs. 

 Triodon was not to be discovered until after the first edi- 

 tion of the "Le Regne Animal," and while its original de- 

 scription appeared in the second edition (1829), it was 

 still not known that Triodon possessed well-developed 

 ribs until Dareste published his 1849 paper. Cuvier could 

 scarcely have been expected to have known the osteology 

 of an as yet undiscovered fish, or to have personally in- 

 vestigated the ribs of every species offish, plectognath or 

 otherwise, described in the "Le Regne Animal." 



The only features that Dareste (1850) believed the 

 plectognaths to have in common were a reduced oper- 

 culum, a rodlike interoperculum, and a low number of 

 vertebrae. To Dareste these characteristics were not im 

 portant enough to merit the recognition of the plectog 

 naths as an order, or even as a natural group. 



One must admit that Cuvier's definition was im 

 precise, but Dareste temporarily neglected (see Dareste 

 1872c:1019) the fact that ordinal definitions are besi 

 founded on a combination of characters possessed by the 

 group in question and not by other fishes. Even ac 

 cepting Cuvier's far-from-perfect diagnosis, it is doubt 

 ful that any fishes other than plectognaths would fit into 

 it. Unfortunately, a significant number of plectognaths 

 also would be excluded from it, but this could be cured 

 by a little rewording. 



Dareste proceeded to split the plectognaths into 

 (1872c: 117) "cinq petites families bien distinctes les unes 

 des autres" which were numbered as follows: 



Premiere Famille - Diodon and Tetraodon 



Deuxieme Famille - Triodon 



Troisieme Famille - Orthagoriscus 



Quatrieme Famille - Batistes (which included "les 

 petits generes Batistes, Alutere, 

 Monacanthe et Triacanthe") 



Cinquieme Famille - Ostracion. 



His definitions of these families were anatomically, and 

 especially osteologically, founded, and included not only 

 a good summation of the contemporary knowledge of the 

 plectognaths but also some original observations. 

 In his later publications Dareste (1872a, b, c) con- 



fined himself to the placement of the scleroderms 

 "among the Acanthopterygians, in the vicinity of the 

 Acanthuri and other fishes belonging to the small family 

 of the Teuthyes" (1872b:68). However, he despaired of 

 showing the relationships of the gymnodonts, for he said 

 (1872c: 1088): "Ce type est assez difficile a definir, par 

 suit de la diversite des formes sous lesquelles il se 

 presente, et qui en font une famille par chaine, plutot 

 qu'une famille en groupe" and (1872c: 1089): "Le 

 Triodon differe notablement des autres Gymnodontes, et 

 forme par consequent un type a part, quoique voisin." 

 Dareste (1872b:69-70) pointed out the many charac- 

 teristics held in common by the "Acanttiuri and Balis- 

 tidae, especially the true Balistes, which are more nearly 

 allied to the Acanthuri than the Triacanthi, Monacanthi 

 and Aluterae." The particular features he noted in 

 Balistes and acanthurids were: firm and immovable 

 union of the premaxillary and maxillary; general shape 

 of skull; supraoccipital with a long forward extension and 

 an elevated crest; ethmoid elongate; parasphenoid as a 

 vertical plate anterior to the orbit; vomer small and 

 toothless; palatine small, toothless, and movable; in- 

 teroperculum at least partially rodlike and hidden 

 beneath the preoperculum; pelvis elongate, its two 

 halves more or less fused together; few vertebrae. In com- 

 parison to these similarities, Dareste said (1872b:70) that 

 "The differences between the skeletons of the Acanthuri 

 and Balistes are but few and of slight importance," these 

 differences being: the presence of suborbitals in acan- 

 thurids and their absence in balistids; the spiny dorsal 

 and soft dorsal fins of acanthurids being continuous, but 

 separated in balistids; the branchial aperture of acan- 

 thurids being larger than in balistids, due to the shape of 

 the preoperculum; the acanthurids possessing true ribs, 

 but not balistids. 



Great credit is due to Dareste for having so definitely 

 pointed out these similarities. They are for the most part 

 correct, although just as Dareste had torn apart Cuvier's 

 definition so also could a person familiar with both acan- 

 thurids and balistids find many osteological details at 

 variance with the above information. But the only 

 reasonable ana useful criticism that can be made of 

 Dareste's scheme is that the comparison was made 

 between acanthurids and balistids rather than between 

 acanthurids and triacanthoids. The triacanthoids are ob- 

 viously the most generalized of the plectognaths and the 

 balistids show every indication of having arisen from 

 triacanthoid ancestors, perhaps not long after the 

 triacanthoids had themselves arisen from an ancestral 

 stock which also gave rise to the acanthurids. Dareste's 

 arguments are still convincing, but they would have been 

 even more so had the comparison been between the acan- 

 thurids and triacanthoids. 



At the same time that Dareste was attempting to dis- 

 mantle the Order Plectognathi, another Frenchman took 

 a diametrically opposed view. Hollard stands second to 

 no one in the study of the plectognaths. While Dareste's 

 primary contribution was to relate scleroderms to acan- 

 thurids, Hollard's was to describe the anatomy and rela- 

 tionships of the families within the Plectognathi. 



