Notes on Luvarus imperialis Raf., a fish new to the fauna of Norway. 21 
ossification, which he describes as follows: — — “ganz kleine 
vielleicht noch in der Entwicklung begriffene Formen, unschein- 
bare Basalplattchen mit einem dtinnen spitz endenden Stachel; Ja 
letzterer an Kalilaugepraparaten noch von einer unverkalkten 
bindegewebigen Substanz umhullt ist, scheint seine Entwicklung 
noch nicht abgeschlossen zu sein” (J. c. p. 14. Taf. I, fig. 27). 
These thin spines may possibly be the same as I have found in 
my specimen, but at an earlier stage of development; they resemble, 
however, more closely the scaletype (abnormal scale without ike 
upper disc? scale under development?) As Hertwig mentions, 
both the caudal and pectoral fin are armoured. In text-figs. 10—12 the 
armour on one of the outer long rays in the caudal fin is depicted, 
one part is at the base of the ray, another in the middle and the 
third towards the tip of the ray, where the armour stops. This 
armour consists of a number of thin spines, which spring from 
a common base; only rarely is the spine double tipped (text-fig. 10); 
each spine is hollow in its whole length, and if the spine be divided, 
each division is hollow. The tips of the spines point inwards tc- 
wards the body’s central axis; they diminish in length distally 
and the row ends in low, isolated spines. The row of spines is 
more developed in my specimens than in Hertwig’s young 
individual, for the spines on my specimens are longer and the 
row reaches farther towards the tip of the rays, while they stop 
in the middle of the rays in Hertwig’s specimen. 
The rays in the pectoral fins for about */, of their length are 
also furnished with a similar consecutive row of spines. 
Based upon my examination of these two specimens of 
Astrodermus, | can agree to Giglioli’s previously-mentioned 
opinion that the Astrodermus-forms are younger stages of 
Luvarus. The difference in the shape of the body is so slight and 
of such a nature, that they may easily be explained as developments 
in growth (the reduction in relative size of head and eye (see table 
p. 30), the shaping of the forehead, development of the caudal 
lateral keel). The scales of Luvarus may well be considered to be 
developed from a type with star-shaped upper plate, which has 
gradually become round as a result of the heaping on of layer 
after layer; the incisions on the edge and the holes, which are 
found at irregular intervals on the plates, being remains of the 
star. The spine armoury, however, appears only to belong to the 
younger individuals, several of these spines are rather loose in the 
