of the Fishery Board for Scotland. 129 
In duseus the ventral fin always extends past the anus, but in minutus 
and esmarkii the tip of this fin often fails to reach the level of the anus. 
Of 18 examples of minutus, in 6 the tip of the ventral fin did not 
reach the anus ; in 3 cases it reached the anus exactly ; and in 9 cases it 
passed the anus. 
Fifty-two examples of esmarkii were examined for this character. In 
20 the tip of the ventral fin did not reach the anus ; in 20 it reached the 
anus ; and in 12 specimens it reached past the anus. 
The tip of the pectoral fin extended past the anus in all the specimens 
ofeach species in which the character was noted, viz., 9 examples 
of duscus, 18 of minutus, and 43 of esmarkiz. 
The Vertebree. - 
The details regarding the variation in the number of vertebre in the 
three species will be found in Tables I., IJ., III., IV. They are 
summarised in Table VI. 
The average number of vertebre was :—Luscus, 48°4 ; minutus, 49°4 ; 
esmarkit, 53°4. 
In the matter of the average number of vertebra, lwscus and minutus 
come very near each other, the latter exceeding the former by one. 
Esmarkit has the comparatively high average of 53:4. The higher 
number of vertebra is accompanied in this species by a higher number 
of rays in the unpaired fins, 
The average number of the vertebra bearing the first hemal arch was 
16 in Zusecws, and the same in minutus, while in esmarkia the average 
was 186. ~ 
The Urinary Bladder and Ureter. 
The urinary bladder in /wscws has no lobe; in minutus and esmarkit 
it has usually two lobes. : 
Luscus.—None of the specimens examined had a lobe to the urinary 
bladder. The bladder in this form is coloured a silvery white. 
Minutus.—In the great majority of cases where this character was 
noted, two lobes were found attached to the urinary bladder, one on each 
side. This was the condition in 12 males and 39 females. In 6 speci- 
mens (3 males and 3 females) one lobe only was made out. In no case 
were both lobes absent. They are diverticula of the bladder, and vary in 
size. Sometimes both are long, narrow processes ; one may be a short 
flap ; or both may be small. 
In one female 23cm, in length the left lobe had a small secondary 
lobe attached to it. 
In a female 25cm. long, captured in March, both lobes were large ; 
they were well supplied with blood-vessels, and their edges were frilled. 
Two of the females got at the same time, measuring 23cm., had similar 
lobes. In another March fish, a male 22cm. long, one lobe only was 
found, and it was well supplied with blood-vessels. Another male, 
22cm., captured in March, had two long lobes which were supplied with 
blood-vessels, but were not frilled. A ripe female in June had large 
frilled lobes. 
Esmarkii.—tIn this form there are usually two lobes to the urinary 
bladder. In four cases, however, no lobe was made out. These fish had 
been for two or three years in the preservative. In 15 specimens one 
lobe only was distinguished, but in the remaining 63 examples in which 
the character was noted both lobes were found. The lobes may be both 
long, or one may be short, 
I 
