66 
ERIK A : SON STENSIO 
a number of supraorbitals, the so-called «Parafrontalia» according to the terminology 
adopted by Reis (1888). As the state of preservation of these supraorbitals is not very 
good it is impossible to determine their exact number, but it was probably not less 
than four or more than six. As far as one can make out they are rather narrow, and 
have been attached lengthways to the fronto-dermosphenotic with their medial margins. To 
what extent they have overlapped the lateral part of the fronto-dermosphenotic is uncertain. 
The supraorbital row of bones is continued in front over the ethmoidal region by 
a large plate of bone (Na. ant, text figs. 20, 21, 25; PI. 5, fig. 1), which to some • extent 
covers the antero-lateral corner of the fronto-dermosphenotic. The relation which the 
bone-plate has to the sensory canal and the external nasal opening in this species is 
not yet clear, but a comparison with other, better preserved forms, which are de¬ 
scribed later on, seems to point to the fact that it may correspond to the nasal elements 
and a great part of the antorbital bone (adnasal) of the primitive Crossopterygii and 
Actinopterygii (cf. the description of Axelia and at the same time my description of 
the Palaeoniscidae , Catopteridae and Saurichthyidae in this work). I have consequently 
called it the nasalo-antorbital. 
Between the nasalo-antorbital of both sides there is found anterior to the fronto- 
dermosphenotics and partly covering their anterior ends, a paired rather large plate of 
bone ( Ptr , text figs. 20, 21, 25; PI. 4. fig. 1; PI. 5, fig. 1; PI. 8, fig. 1), which I have 
called the postrostral. The two postrostral plates meet medially in a rather long suture 
which forms a direct anterior continuation of the suture between the fronto-dermo¬ 
sphenotic bones. With regard to the homologues of the postrostral plates and the rest 
of the membrane bones on the dorsal side of the ethmoidal region, I shall return to 
this question in my description of Axelia robusta and in the chapter headed, «Coela- 
canthids compared with some other fishes, and certain Tetrapods*. 
As all the membrane bones of the cranial roof are preserved as impressions of 
the medial side or else are found in a much weathered condition nothing can be decided 
in respect to their ornament. 
Although not belonging directly to what has preceded in this part, it ought to 
be mentioned that a sclerotic-ring is found developed in W. sinuosa, and consists of 
about twenty quadrangular bone-plates ( Scr, text fig. 25; PL 5, fig. 4; PI. 6, fig. 2). 
The membrane bones of the cheek. 
The dermal bones of the cheek in W. sinuosa are partly well preserved and lie 
pretty well in situ. One finds the three boneplates, which in general are a distinguishing 
feature in the Coelancanthids, lying in a vertical row postorbitally, and anterior to them 
the long bow-shaped bone, called in the current terminology of palaeontologists the 
suborbital, as indicated by the name, below the orbital opening. As it is more convenient 
to put off giving an account of the homologues of the four bones mentioned until it can 
be done in connection with a description of the sensory canals of the head, I shall only 
remark here that in the subsequent description I shall confine the term postorbital to 
the dorsal of the three postorbital plates and that I shall introduce for the middle one 
the term squamoso-preopercular and for the ventral one the term preoperculo-quadratojugal. 
The suborbital I shall call the lacrymo-jugal. 
