STRUCTURE AND AFFINITIES OF THE PLATYSOMIDA. 345 
These views as to the position of Platysomus met with very considerable 
acceptance ; accordingly we find, in the systematic works of GrrnitTz,* PicTET,*t 
and M‘Coy,{ this genus included in the family Pycnodontide. 
Nevertheless there were some dissentient voices. Voar, in his classification 
of the Ganoids, published in 1852,§ continued to associate Platysomus, as well as 
ELurynotus, with the Paleonisci, placing them together in the subfamily “ Palw- 
onisciden” of the family Monosticha. HecKEt|| and WAGNER,1 both of whom 
had laboriously studied the Pycnodontide, also declined to admit into that 
family either Platysomus or Tetragonolepis (Pleurolepis, Quenstedt), the latter 
genus having also, on account of its scales, been subsequently brought by 
Sir Puizip Grey-Ecerton under the same category. Their objections as 
regards Platysomus were chiefly founded upon its heterocercal tail, fulcrated fins, 
and non-possession of the peculiar premandibular bone, or “ Vorkiefer” of the 
Pycnodonts. With regard to the teeth of Platysomus macrurus (Eurysomus, 
Young), and those of Globulodus, Dr WAGNER recalled attention to the fact that 
AGASSIZ originally hesitated to recognise the latter as Pycnodont, adding,— 
“Tch setze hinzu dass die Zahne von Platysomus die grésste Aehnlichkeit mit 
denen des Lepidotus zeigen, also keinesweges auf die Pycnodonten hinweisen,” 
stating also that we knew nothing of the condition of the upper jaw in Platy- 
somus. He admitted that the form of the body and of the scales were in favour 
of Pycnodont affinities ; the other characters were, however, either not exclusive, 
or in contradiction with the peculiarities of the Pycnodonts. Dismembering 
the old “Lepidoidei” of Agassiz, Dr WAGNER now proposed to constitute a 
new family of “ Stylodontes,” which should include besides Platysomus, also 
the genera Pleurolepis, Quenst. (= Tetragonolepis, Bronn, Egerton),Homcelepis, 
Wagner, Heterostrophus, Wagner, Dapedius, Dela Beche, and Tetragonolepis, 
Agassiz (= dichmodus, Egerton). We shall see in the sequel that the associa- 
tion by Wagner of Platysomus with those other genera is just as unnatural as 
the classification which he himself wrote to oppose. 
In 1866, however, Professor Younc,** in a well-known paper, declined to accept 
the peculiar dentition of Platysomus macrurus as characteristic of all the species 
which had been referred to that genus, and recalled attention to the “dents en 
brosse,” mentioned by Aaassiz in his generic definition, which he said “are not 
Pycnodont, but Lepidoid (=Lepidosteid).” Minutely describing the structure, 
of a small Carboniferous fish, which he referred to the Platysomus parvulus of 
Acassiz, he stated that it also had its jaws “armed with slender conical teeth,” 
* Dyas, Leipzig, 1861, p. 8. + Traité de Paleontologie, 2d ed., 1854, vol. ii. p. 208. 
{t British Palzozoic Fossils, p. 614. § Zoologische Briefe, vol. ii., Frankfurt, 1852. 
|| Beitriige zur Kenntniss der fossilen Fische Oesterreichs, Denkschr. Ac. Wien. xi, 1856. 
“I Miinchener gelehrte Anzeigen., Bd. L., 1860, pp. 80-99. 
** On the Affinities of Platysomus and Allied Genera, “ Qu. Journ. Geol. Soc.” 1866. 
