LINNEAN SOCIETY OF LONDON. 3 1 



lateral vessels whicli started from the main vessel to reaet the 

 ampullae. This method will do when there is no overlap of 

 ampullfe, and it proves that Valentin was correct. But the 

 second vessel is drawn by the French observer as if it were 

 I)laced over (or more properly, from the natural position within 

 the test, within or internal to) the very visible ordinary vessel. 

 It could hardly be counted. 



I therefore dissected out a rectangular piece of soft parts 

 which included several ampullae, son* length of main water- 

 vessel, and all the lateral offshoots. The piece was transferred 

 to absolute alcohol, stained with picro-carmine, and cleared in 

 the usual manner. Owing to the action of the alcohol the 

 originally flabby morsel was made more rigid, but very fragile. 

 It was transferred in parts to the glass with great difficulty, 

 for the preparation could not be teased out without endangering 

 the perfection of the water-system. By using the flat remover 

 some fairly good pieces were safely transferred. 



In one preparation two ampullae are seen, one to the right and 

 the other to the left ; each is supplied by a delicate water-tube, 

 and the water-tubes spring from a small portion of the main 

 water-vessel. In the second preparation two or three water- 

 vessels are seen, one above the other, and their ampullae have 

 been removed. In both preparations there is no evidence of a 

 second water-vessel springing from the main water-tube and 

 passing to an ampulla. 



So far as Psammechinus, Strongylocentrotus, Salmacis, and 

 Temnopleurus are concerned, I have found Valentin's description 

 true. 



The power to be used is that conveyed by a lens of 1-inch focal 

 distance, or one of |-inch. A good hand-lens will almost 

 suffice. 



On the Northern Distribution of Oxalis cernua, Thunb.* 

 By the Eev. Prof. a. Henslow, M.A., F.L.S., F.G.S., &c. 



[Read 2ncl April, 1891.] 



This plant is a native of the Cape of Good Hope, and has often 

 been described by botanists who have studied the Cape flora f. It 

 has become distributed not only on the islands of the Atlantic, 

 as the Bermudas, Canaries, and Madeira, but along both the 

 north and south coasts of the Mediterranean Sea. At the pre- 

 sent day it is found at various places, from Egypt to Morocco, 

 and from Gibraltar to the Greek islands. The question is, bow 

 did it come to be so widely distributed throughout the Medi- 

 terranean region ? 



* Thunbei-g, Biss. No. 12, t. 2. f. 2 (1794). 



t E. (/., Harvey and Sonder, Flora Capensis, i. 348 ; and Thunb. Fl. Cap. ed. 

 Scliult. 537 (1825). Schultes describes Oxalis cernua as flowering at the Cape in 

 June and July. It has completely changed tiiis habit in tlie north, as it is in 

 full blossom all through the winter, from November to April. 



