Natural History of British Animals. 239 



ventral surface white ; avenues of suckers yellowish ; whole sur- 

 face very smooth and soft. The yellowish-white spots on the 

 dorsal surface are, when the animal is contracted, minute round 

 depressions, from which, in a state of expansion, conical tran- 

 sparent tubercles are protruded. On the ventral surface, slight- 

 ly elevated striae extend between the marginal spines and the 

 sucker canals. The dorso-marginal plates are not seen when 

 the animal is ahve. There are 88 suckers, arranged in two 

 rows, in each canal. The suckers are moved about slowly, and 

 adhere feebly. 



Found under stones amongst sandstone cliffs, at Whiting Bay, 

 Arran. 



Synoicuni., (De Blainville, Man. de Malacol. p. 586, a genus 

 in which several of Savigny's genera of compound Ascidiee are 

 united); S. rubrum, C. (Plate II, Figs. 8, 9, 10 k 11.)— Form 

 of general mass various ; base, for the most part, cylindrical ; 

 summit larger, more or less conical or convex, sometimes di- 

 vided ; height nearly an inch ; base yellowish, translucent, 

 somewhat cartilaginous ; summit containing the animals im- 

 bedded in its substance, and coloured by them of a bright 

 vermilion ; animals very numerous in each lobe, and crowded 

 together without any regular arrangement ; orifices prominent, 

 with their margins divided into eight or nine short tentacula. 

 The size and outline of each animal, separated from the common 

 mass, are represented in Fig. 10, and a magnified view of the 

 same is given in Fig. 11. 



Found in abundance on the north shore of Lamlash Bay, 

 Arran, attached to the sides of boulders, generally under the 

 shelter of fuci. 



Sidnyum iurbinatum, (Savigny, Mem. 238.) ; Sydneum, 

 (Flem. Brit. An. 469). — In specimens from St Ninian's Point, 

 on the west coast of Bute, I found from 5 to 20 animals set 

 round the circumference of each lobe. 



Ascidia Prunurn, (Lamarck) ; Pirena prunum, (Flem. Brit. 

 An. 468)*. Branchial orifice with nine short conical tentacula : 



• I do not adopt llic latter generic name, because Ijamarck has already 

 assigned it to a genus of fresh-water moUusca. (An. sans vert. vi. (2.) 169) 



