1904 - 5 .] Report on Medusae found in Firth of Clyde. 767 
I know from experience that sense-organs of Aglantha are not 
always to be found in preserved specimens. I remember spending 
several days searching for them on the margin of the umbrella 
of a large number of Aglantha preserved in formalin. It was 
necessary to find out whether there were four sense-organs or 
eight sense-organs for the purpose of determining the species. In 
many specimens the sense-organs were not to be seen ; in others 
one, in others two or three, and in others more were found. 
These sense-organs are minute ; and unless the specimens are very 
carefully preserved and in good condition at the time of preserva- 
tion, the chances of seeing the sense-organs are very small indeed. 
Melicertum proboscifer has its stomach on a long and con- 
spicuous peduncle ; the gonads are upon the eight radial canals on 
the sub-umbrella, and the tentacles (taf. ii. fig. 6), as shown in 
one octant of the umbrella, are quite characteristic of the 
Aglauridae I think that this species had better be transferred to 
the genus Agliscra. 
Mitrocomella polydiademata (Romanes). (Table II. 17.) 
Tiaropsis polydiademata , Romanes, 1878, vol. xii. p. 524; 
vol. xiii., pi. xv. fig. 3. 
Mitrocomella polydiadema , Haeckel, 1879. Browne, 1895, 
vol. ix. p. 279. 
In 1902, a specimen was taken on 27th June and another on 
11th July. 
Description of the specimen taken on 11th July: — The 
umbrella is somewhat globular (the shape is partly due to 
the contracting inwards of the margin of the umbrella), with very 
thick walls; a little broader than high. Velum narrow. The 
stomach is small, with a quadrangular base. Four radial canals. 
The gonads are linear, extending over the outer half of the radial 
canals, and nearly touching the margin of the umbrella. Large 
ova are present along the whole length of the gonads. Tentacles 
thirty-six, which are long and slender, with cone-shaped basal bulbs. 
Between every two tentacles there are numerous cirri, about 
four to ten, the number depending upon the distance which the 
tentacles are apart. The cirri are very long and slender when 
fully expanded, and terminate in a small oval cluster of nemato- 
