320 Illustrations in British Zoology : — 



Art. IV. Illustrations in British Zoology. By George John- 

 ston, M.D., Fellow of the Royal College of Surgeons of Edin- 

 burgh. 



12. Dianje^ Bai'rdij. (fgAl.) 

 CI. Radiata, Ord. M611ia, Fam. Medusicte. 



a ^- — ^~— -^ 41 



The specimen here delineated of this beautiful species of 

 Medusa, or sea jelly, was taken in Berwick Bay on the 27th of 

 September, 1832, floating on the surface of the water, in which 

 it moves by alternate contractions and dilatations of the cir- 

 cumference of the body. Our figures represent it of the natural 

 size, the first (a) being a view of it when looked on from above ; 

 the second (b) when looked on from below. It is a semi- 

 globular mass of a perfectly translucent and almost colourless 

 jelly, divided, by four opake milk-white narrow ligaments, or 

 bands, into four equal compartments. These bands arise at 

 the angles of the mouth, and are at first very fine, but become 

 broader and somewhat curled in their course towards the 

 upper surface. The very delicate membrane investing the body 

 is folded at the margin, which is furnished with a circle of rather 

 distant tapered white tentacula. In our specimen there were 

 thirteen of these. The under side is produced in the middle, 

 so as to form a kind of stalk, at the apex of which is the mouth, 

 of a square form, and encircled with four white plumose 

 branchial appendages. When magnified, these are shown to 

 be formed of a thin membrane, beautifully but irregularly 

 folded like a frill, and edged with a neat thickened border. 



Dianse\z Baird/z seems to be invested with two membranes 

 of great tenuity. The outer one covers all, like as it were a 

 a glass inverted over a smaller globe, the intermediate space 

 being occupied with a consistent but colourless jelly, in which 

 neither vessels nor membranes can be distinguished. This 



(p. 1^0.) in honour of Mr. Mathews. On tab, cii. (part viii.) is figured 

 Bridges^ spicata, which Messrs. Hooker and Arnott have named (p. 168.) 

 in honour of Mr. Bridges. — J. J). 



