1870. | HANCOCK AND HOWSE—DORYPIERUS HOFFMANNI. 629 
The posterior extremity, however, is a little enlarged, and appears to 
have been the articular surface. 
The enlarged part of the anal fin (6) is placed near to the transverse 
centre of the body. Itis about half an inch long, and is triangular, 
with the extremity pointed, the posterior margin being slightly con- 
vex, the anterior straight or a little concave. The base extends 
nearly as far forwards as the posterior ventral plates, being prolonged 
in this direction by seven or eight pointed scale-like rays or plates, 
which diminish in length forwards; and it is continued backwards to 
the root of the tail as a low fringe (6’), about =, inch wide, supported 
by rather distant delicate rays, but whether jointed or not could not 
be determined. The anterior elongated portion is composed of be- 
tween twenty and thirty simple, jointed rays, the joints being rather 
long, with the articular extremities shghtly enlarged. 
The dorsal fin (a) has a very extraordinary development ; its ante- 
rior elongated portion is estimated to be as long as the whole fish 
minus the tail, and rises up from the dorsal ridge a little in advance of 
the centre, consequently just in front of the position of the anal fin, 
in the form of a scimitar slightly bent forwards. It seems to have 
been in the larger specimens upwards of 4} inches in length, and is 
extremely narrow, being only ;7, inch wide an inch from the base, 
gradually tapers to a fine point above, and as gradually widens down- 
wards to within 2 inch of the base, which suddenly expands, stretch- 
ing forwards almost as far as the occiput, and backwards to the root of 
the tail, as a narrow fringe, similar in height and appearance to that 
on the opposite or ventral margin. The anterior prolongation (a’) is 
composed of a double lateral series of about twelve low, stout, pointed, 
scale-like rays or processes, the fin-fulcra, inclining and increasing 
in length backwards. ‘The first of the seriesis extremely short, just 
appearing above the dorsal ridge ; the last is about 54, inch in length; 
and the whole, leaning in the direction of the fin, one supporting 
the other, form, as it were, a sort of buttress to the base of the 
enormously elongated fin. Only a few of the central rays reach to 
the top of this elongated portion of the fin; both in front and be- 
hind they die out gradually. At the base, Just above the anterior 
fin-fulera, there are twelve or thirteen rays; halfway up they are 
reduced in number to seven or eight; and within half an inch of the 
top, judging by the upper portion of a fin in our possession, there 
are only four or five. All the rays are divided into numerous and 
unusually elongated joints (fig. 4), which at the points of articulation 
are slightly enlarged. The joints are longest in the centre or anterior 
rays, some of them measuring +/, inch in length. 
The tail is distinctly heterocercal, and is deeply and regularly 
forked, the upper lobe being only a little longer than the under. 
The former is 1} inch in length; and from tip to tip of the lobes the 
tail is 13 inch in width. The anterior margin of the upper lobe is 
defended by a closely arranged series of stout, sharply pointed, ena- 
melled, scale-like processes or fin-fulera (fig. 1, f), which imbricate 
and diminish in size backwards. Behind or below these there is a 
double row of rhombiform scales (¢), likewise covered with enamel 
