or a group of supposedly related species. For example, 

 Chapter I (p. 143-148) was devoted to "De Orbe Pisce" 

 and described 11 species in which the first word of the 

 binomial or polynomial was, in all but two cases, Orbis. 

 The two exceptions had the species name beginning with 

 Orbibus or Histrici and are diodontids. One might ex- 

 pect that all of the Orbis species would be tetraodontids 

 or diodontids and in fact they are, with a single excep- 

 tion: the Orbis Ranae rictu (p. 145, fig. 2 of pi. 19, after 

 Clusius) is Cyclopterus lumpus. Another species, Orbis 

 oblongus Testudinis capite (p. 147-148, fig. 3 of pi. 19, 

 after Clusius) is probably a tetraodontoid, but the figure 

 shows a creature whose front end reminds one of a fetal 

 seal but whose hind end is fishlike. Chapters II (p. 148) 

 and III (p. 148-149) described, respectively, Ostracion 

 Nili and Ostracion prior, both of which are ostraciids, as 

 is Pisces triangularis of Chapter IV (p. 149-150). Chap- 

 ter V (p. 150-151) described Monoceros pisces, which is 

 probably a monacanthid, while Chapter VI (p. 151-152) 

 was devoted to the Mola of Salviani or Orthagoriscus 

 of Rondelet. Chapter VU (p. 152-156) described the 

 balistid Capriscus pesce Balestra, but an appendix to 

 this chapter described three species of Orbes: a 

 tetraodontid, a diodontid, and an ostraciid. The remain- 

 ing seven chapters described nonplectognaths, these be- 

 ing, to use only the "generic" term, Stromateus (a but- 

 terfish), Hippocampus (a seahorse), Acus (a pipefish), 

 Acui (a syngnathid), Scolopax (Macrorhamphosus), and 

 Xiphias (a swordfish). The latter seven types have little, 

 if anything, in common with the plectognaths, making 

 for an odd mixture of forms within the "Pinnis ven- 

 tralibus carentes," but it is more realistic to dwell on the 

 fact that by the 17th century the plectognaths were al- 

 ready placed together in the same subgroup of fishes. 



In an appendix, written by Lister, to Willughby's 

 (1686) "Historia Piscium," an illustration of a shallow- 

 water triacanthid was given, based on the Hoornvisch of 

 the Dutch East Indies first described by Nieuhof (1682) 

 in his work on the fishes of Batavia. An account of 

 this species of triacanthid was not to reappear until 

 Bleeker (1852b) formally described this first-mentioned 

 triacanthid as Triacanthus Nieuhofii, while in the in- 

 terim the first triacanthid to be binomially described was 

 Batistes Biaculeatus Bloch 1786. By contrast, the deep- 

 water triacanthodids were not described until Schlegel 

 (1850). 



With the advent of Artedi, the classification of fishes 

 in general as well as that of the plectognaths was placed 

 on a much more refined basis, for the groupings of sup- 

 posedly related forms were far superior to any that had 

 previously appeared. In his "Genera Piscium," Artedi 

 (1738) recognized five basic divisions within his Pisces. 

 One of these, the Plagiuri, had the caudal fin horizontal 

 and is the Cetacea, while the other four divisions (Mala- 

 copterygii, Acanthopterygii, Branchiostegi, and 

 Chondropterygii) had the caudal fin perpendicular and 

 are true fishes. The Branchiostegi contained the fol- 

 lowing genera: Batistes, Ostracion, Cyctopterus, and 

 Lophius. 



The generic categories of Artedi are usually recog- 



nized today at the familial or ordinal levels. The name 

 Branchiostegi {branchio, gills, and stegein, to be 

 covered) implies that Batistes, Ostracion, Cyctopterus, 

 and Loph'us should have the superficial similarity of the 

 gills being relatively well hidden from external view by 

 the constricted aperture of the branchial cavity. We now 

 know, of course, that the last two genera mentioned 

 above are neither closely related to one another nor to 

 Batistes and Ostracion. Ostracion contained 22 species 

 which represent not only the ostraciids but also the 

 tetraodontids, diodontids, and molids. It should be noted 

 that the Ostracion category was composed of species of 

 extreme diversity in external appearance, which are 

 nevertheless closely related to one another. Moreover, 

 the group was not as heterogeneous as it might super- 

 ficially seem to be, for within it the species were de- 

 scribed successively in a manner which shows that Artedi 

 had an insight into the relative closeness of relationship 

 of the various forms. Thus, the first 10 species are os- 

 traciids, and the next 3 species are tetraodontids. All of 

 the next seven species (nos. 14 to 20) are diodontids, with 

 the exception of species no. 17, which is the Orbis Ranae 

 rictu of Willughby and of Clusius, a cyclopterid. The 

 next to the last species (no. 21) is probably a tetraodon- 

 tid, but since it was based on the poorly figured Orbis ob- 

 tongus Testudinis capite of Willughby and of Clusius, 

 one could scarcely have expected Artedi to have placed it 

 with his other tetraodontids. The last species (no. 22) is 

 the commonest (as an adult, at least) of the molids, Mola 

 mola. The Batistes group contains five balistoids and a 

 macrorhamphosid (the only nonplectognath included). 

 In short, Artedi did justice to those plectognaths which 

 he had actually seen or which were reasonably described 

 in the literature, and the several errors were only the 

 result of occasionally being forced to rely solely on poor 

 descriptions by earlier naturalists. 



The plectognaths appeared in a somewhat different 

 assemblage in Klein's (1742) "Historiae Piscium 

 Naturalis." Like previous workers since the time of 

 Aristotle, Klein included in his Pisces both cetaceans 

 and fishes, separating them from one another on the 

 basis of possession of lungs or gills. Whereas Artedi's first 

 dichotomous division of the true fishes was on the basis 

 of bone as opposed to cartilage in the skeleton, Klein's 

 was on whether the gills were hidden or easily observed. 

 Thus, the Branchiis Apertis contained a large array of 

 relatively normal fishes, such as Siturus, Acipenser, 

 Xiphias, Mastacembetus, Sotea, Tetragonopterus, etc. 

 By contrast, the Branchiis Occultis contained a less 

 plausible association of 15 genera, including elas- 

 mobranchs and cyclostomes. 



The plectognaths were all included in Crayracion 

 (Klein 1742:17) and Capriscus (p. 23), which, along with 

 Batrachus and Conger, supposedly had the following 

 combination of characters: paired fins present; 

 branchial cavity with a single aperture; gills placed 

 laterally and hidden from view. Klein's Batrachus is the 

 same as Artedi's Lophius, while Artedi's Cyctopterus ap- 

 peared as a part of Klein's Crayracion. The addition of a 

 number of eels, as Conger, to a place of proximity with 



