Dr. R. H. Traquair on the Anatomy of Calamoichthys. 115 
the first of the series of well-developed upper ribs, which extend, 
in the horizontal intermuscular septum, as far back as the ninety- 
eighth vertebra. But ribs of the lower series are very deficient in 
development i in comparison with those in Polypterus, where the 
whole series of abdominal vertebre, except the first, is furnished 
with those appendages, which posteriorly attain a considerable 
length. In Calamoichthys, on the other hand, those lower ribs are 
very minute, and no trace of them was found in advance of the 
sixtieth vertebra. The number of abdominal vertebra, in the 
specimen alluded to, is 100, of caudal 1U—showing the very great 
proportional elongation of the abdominal and shortening of the 
caudal region. The vertebral column projects beyond the last 
caudal vertebra, as a notochordal continuation or “ urostyle” 
concealed among the rays of the caudal fin. The bones sup- 
porting the fins agree in their general conformation with those 
in Polypterus, there being, however, a less ossified state of the 
radius, ulna, and carpus, “while the ‘pelvic bones, along with the 
ventral fue are completely absent. The first dorsal finlet is 
placed opposite the forty-ninth vertebra. 
As regards the form and arrangement of the bones of the 
cranium and face, the most complete correspondence is found 
with those of Polypterus, a space being found, however, below 
the preoperculum, which, in various species of Polypterus, is 
defended by a variable number of bony plates. The suboper- 
culum is also completely absent. The arrangement of the 
mucus-canals on the head is similar to that in Pian 
The arrangement of the muscular system corresponds in the 
two genera. In Calamoichthys, owing to the great increase of 
the number of vertebree, the number of transverse segments of 
the great body-muscle is also much larger. The muscular layer 
along the belly is very thin. 
Viscera.—The cesophagus dilates into a flask-shaped stomach, 
which terminates behind in a cul-de-sac. From the interior part 
of the stomach, and close behind the entrance of the cesophagus, 
issues the intestine, which passing first slightly forwards, makes 
almost immediately a turn on itself, and then proceeds straight 
back to the anus. A small cecal appendage, with the apex di- 
rected forwards, is seen i connexion with the intestine shortly 
after its backward flexure; and a little further down, between 
this and the anus, a spiral valve of about five turns is developed 
in the interior. The liver was in none of the specimens exa- 
mined very voluminous, but much elongated, being continued 
as a narrow stripe the whole length of the abdominal cavity. 
The gall-bladder is distinct, and opens into the intestine imme- 
diately after its flexure, and in front of the caecum. 
The heart is conformed as in Polypterus, with muscular bulbus 
