76 REPORT—1849, 
Pilidium, is proposed, to which Patella ceca of the ‘ Zoologia Danica’ also belongs ; 
and for the latter a new genus, Propilidium. Pilidium is allied to Acmea on the 
one hand, and to Propilidium on the other, having the position in the shell of the 
former genus, and the tongue of the latter. Propilidium links Acmea and its allies 
with Puncturella and Emarginula, like which it has the apex of the shell turned away 
from the head of the animal, but has a very different dentition. 
The British Patellacea may be arranged as follows :— 
Ist Group. Parextina#. Cyclobranchiate animals; apex of the shell anteal. 
1. Patella. A. Branchial lamine extending in front of head; branchial impression 
in shell unsymmetrical. 
1. Patella vulgata. 
2. Patella athletica. 
B. (Patina). Branchial laminz deficient in front of head; branchial impression 
subsymmetrical. 
3. Patella pellucida, 
2nd Group. Acmzavz. Branchiz cervical ; apex of shell variable ; rachis of tongue 
of comparatively single elements. 
1. Acmea. Transverse element of tongue double; tentacula oculiferous; apex of 
shell anteal. 
1. Acmza testudinalis. 
2. Acmea virginea. 
2. Pilidium. Transverse element of shell anteal. 
1. Pilidium fulvum. 
3. Propilidium. Transverse element of tongue single; tentacula eyeless; apex of 
shell posteal. 
1. Propilidium ancyloide. 
Then follow Emarginula (two species); Puncturella (one species) ; and Fissurella 
(one species); all members of a third group, linking the two former with Haliotis and 
Trochus. Capulus and Calypirea are members of another family. 
On Beroé Cucumis, and the Genera or Species of Ciliograda which have been 
founded upon it. By Prof. E. Forszs, F.R.S. 
At the Birmingham Meeting of 1839, the author, in conjunction with Professor 
Goodsir, communicated an account of the British Ciliograde Meduse. They then 
announced the existence in our seas of the true Beroé Cucumis of Otho Fabricius, 
which they had taken on the coasts of Zetland. 
Since that time Prof. E. Forbes has availed himself of many opportunities for the 
observation of these animals, and has been successful in discovering some new features 
in their economy. He has taken the Beroé Cucumis in many parts of the coasts of 
England and Scotland, from the Zetland Isles to the Isle of Wight, and has not been 
able to find any sufficient differences among the individuals to warrant the recognition 
of more than one species. They vary greatly in size and colour; in the Hebrides 
they are not unfrequently taken 3 inches in length, but are usually very much 
smaller on the English shores. He has found that apparently at certain seasons nu- 
merous individuals of this Beroé produce in the line of their ciliary ribs, and from 
the belts of motor tissue at the base of the cilia, ovate egg-like pedunculated bodies 
of a bright orange colour. These can also be produced from the finer ciliary circles 
of the mouth and of the dorsal extremity. When the animal is in this state, any 
irritation near the ciliary ribs causes it to contract the neighbouring portion of the 
body over them, so as to protect them, sheathing the eggs as it were in deep mem- 
branous canals. Particular attention is directed to these gemmules or egg-like bodies, 
which may prove to be intermediate states of the Beroé. When the animal is in egg 
it is extremely irritable, and when irritated gives out the most brilliant vivid green 
phosphorescent light, always from the vessels beneath the ciliary ribs and from no 
other part. 
The badness of the majority of delineations of this animal and a misconception of 
its true structure, have caused numerous false species and several genera to be con- 
structed out of one. Thus in the ‘ Histoire des Acalephes,’ by Lesson, all the fol- 
lowing appear to be founded on Beroé Cucumis: in the genus Beroé, Beroé Forskahlii, 
