256 
ERIK A : SON STENSIO 
cimens of Perleidus altolepis or a species closely related to this may be present, although 
their state of preservation makes a proper identification of them difficult. A supposition 
of this sort is possible both in the case of the specimen figured by him in PI. VI, fig. 3 
as Heterolepidotus serratus Bellotti and the one that in his PI. IX, fig. 6 he calls Pholido- 
phorus barazatti Bassani. In any case it seems to be clear that the former specimen can¬ 
not be referred to Heterolepidotus. 
The type specimen of Perleidus altolepis is in certain respects incompletely and 
incorrectly described in the previous literature (Deecke, 1888, pp. 120—121; de Allessandri, 
1910, pp. 49—51), and as the second newly-discovered specimen in the Senckenberg 
Museum helps considerably to increase our knowledge of the 
genus Perleidus as a whole, I consider it necessary to communi¬ 
cate some of my own observations. 
The relation and the appearance of the membrane bones 
of the cranial roof is partly shown in text fig. 78 A, which can¬ 
not lay claim to any very great degree of accuracy with regard 
to the finer details, but still reproduces what can be distinctly 
observed. Text fig. 78 B is a similar sketch showing the skeleton 
of the jaws and oper cular apparatus. Of special interest is the 
large palaeoniscid-like preoperculum (Po) that is clearly preserved 
on both the specimens in the Senckenberg Museum (cf. de 
Allessandri, 1910, p. 50; Stolley, 1920, p. 65). The scales (text 
fig. 79) are only partly serratad on the posterior margin, the 
upper part of this margin being entire. The ridg-e-scales are 
very indistinctly preserved, so that nothing certain can be said 
as to their shape, in spite of express statements to the contrary 
both by Deecke and de Allessandri. Besides the main lateral 
line of the body we can distinguish also a shorter dorsal body 
line running dorsally of the former from the region of the neck 
backwards towards the anterior marg'in of the dorsal fin. 
In connection with his revision of the genus Colobodus 1920 
Stolley (pp. 38 , 40—41, 84—85) arrived at the view that the 
species described by Woodward (1912, pp. 296—297) from Spitz- 
bergen under the name of Colobodus altilepis does not really belong to the genus 
Colobodus in the restricted sense that this genus ought now to have according to my own 
(Andersson 1916 a) and his (1920) investigations. Stolley is in addition of the opinion 
that Colobodus altilepis A. S. Woodward ought either to be put in connection with 
the species Colobodus ornatus (Agassiz) and Colobodus latus (Agassiz), for which he suggests 
the new generic name Parolepidotus, or with Heterolepidotus dorsalis Kner. 
The new material of Colobodus altilepis A. S. Woodward now at my disposal shows 
undoubtedly that Stolley’s view is correct inasmuch as this Species cannot belong tO' 
the genus Colobodus s. str. On the other hand it is, however, equally clear, as we shall 
see, that Stolley is wrong in his considerations as to the affinities of this species. 
With regard to the head skeleton Colobodus altilepis A. S. Woodward belongs to the 
Palaeoniscid type and seems, as far as is known, to be very closely connected on the 
Text fig. 78. 
Perleidus altolepis Deecke. 
After P.I258 in theSenckenberg 
museum in Frankfurt am Main. 
A) Sketch ofthemembrane bones 
of the cranial roof. 
B) Sketch of the opercular, ske- 
Ext, extrascapular; Fr, frontal 
Ifo, row of infraorbital bones 
Md, mandibular; I/.v,maxillary 
Op, operculum; Pa, parietal; 
Rbr, branchiostega] radius; 
So, supraorbitals; Sop, suboper- 
