24 Sigurd Johnsen. 
The only thing that might seem to point to Astrodermus being 
of a different species from Luvarus, or that the former contains not 
only Luvarus in young stages of development, but also a separate 
species, is a remark of Risso.*) Speaking of his species, Diana 
semilunata, he writes (p. 268): “La femelle est pleine d’oeufs en 
été”. He gives the size as being 0.420. There has been no later 
confirmation of this statement. In my young specimens the sexual 
glands are exceedingly small. Unless Risso’s statement is based 
on a very close examination, it may be explained in the following 
way. When I opened one of my specimens, I was astonished to see 
the great resemblance of the ventricle to an ovary. The papillae 
with the circle-shaped base were clearly visible through the thin 
wall of the stomach, as compact, white bodies, giving the appear- 
ance of an ovary full of large eggs. The ventricle lying immedia- 
tely over the anus can also explain, that it has, after a cursory 
examination, been taken for an ovary. There is yet another state- 
ment made by Risso, which may lead to doubts as to whether 
the forms mentioned all belong to one species. Speaking of his 
species, Auwsonia cuvieri, he mentions (page 342) the size as being 
0.360, smaller than his specimen of Diana semilunata. His 
description suits Luvarus imperialis, so that Ausonia is considered 
‘as identical to it. The maximum size of Astrodermus is by 
Moreau (1881) given as 0.420 m., while the minimum jor 
Luvarus is given as being 0.6 m. There is thus a lacuna of 18 
cm. in the series from Astrodermus to Luvarus during which the 
reduction in the number of rays in the vertical fins must be con- 
sidered to occur. That this reduction takes place gradually is 
likely, according to what has been mentioned in the foregoing 
pages, concerning the appearance of free rays in front of these 
fins; my statements too, with regard to the changes in the caudal 
fin show that these occur gradually. 
Considering the great similarity in the shape of the bodies of 
Astrodermus and Luvarus, there seems no reason to suppose that 
there should be any reduction in the length of the body during the 
metamorphosis, a reduction of 14 per cent, if Risso’s statement 
of the size of his Ausonia be correct. 
Risso’s illustration 28 depicts a Luvarus with a very slim 
body; the height of the body, in proportion to its total length 
1) Risso, A.: Hist. nat. de PEurope Mériodinale. T. III. Paris 1826. 
