184 William Sörensen 
prevents it from all sideward movements. At its base it has behind 
a thick hookformed process (A), whose naked but very faintly exca- 
vated hindside can be brought into full contact with the very slightly 
convex, nearly plane, naked foreside of the second, rudimentary ray. 
This ray is essentially of the same form as in Balistes, provided 
with two downwards- and outwards going arms, which are connected 
by means of diarthroses with the interspinous bone and which are 
continued beyond the diarthrosis into a muscular process, to which 
its M. posterior (p2) is fixed. The diarthrosis is not very tight, but 
in front and still more behind the ray is conneeted with the inter- 
spinous bone by means of long ligaments, of which the hindermost 
(4’) is fixed to the ray just above the diarthrosis. On its lower side 
the ray has in the middle line a naked part formed of two faces 
meeting each other at an angle of about 120° in the shape of a 
roof. This part corresponds with a concave, naked face at the top 
of the, but slightly prominent, middle keel of the interspinous bone. 
(The hindmost end of this face is seen at 0’.) Between the upper 
tip of the rudimentary ray and the upper end of the hookformed 
process of the first ray is found a flat and broad but not very 
strong ligament.« 
To this description I had added the following note: »In this 
respect M. Gunnii! appears to differ in some measure. Cf. Taio 
op. cit. pag. 13—14. — When this author has a somewhat different 
opinion as to the activity of the muscles, it is, I suppose, owing to 
his not having understood the function of the fixing? faces. Thus 
he supposes the naked scouring faces on the rudimentary ray and 
the interspinous bone to form a diarthrosis; but the real diarthrosis 
he has not seen.« — Besides the said slight but very essential 
mistake in his translation Dr. Tuimo in his last paper reports 
my opinion to be that »an dem Stachel [the first ray] hatte ich [Dr. 
Tuto] das eigentliche Gelenk gar nicht gesehen.« Here again I 
have met with my usual misfortune to be misunderstood by Dr. 
T#ıLo: on this subject I had said nothing whatever. A different 
thing is that I ought to have added that he had also overlooked 
the scouring faces on the backside of the first and on the foreside 
1 The figures from this species are reproduced, in the figg. 1 and 2 of Dr. 
THILO’s recent memoir, as being from »Monacanthus (sp. ?)<«. 
2 Not as Dr. TuıLo translates >fixirten« by which slight variation my 
tatements becomes sheer nonsense. 
