On the Tetrasporic Fruit of the genus Stenogramme. 481 



the foot of C denticulatus is entire ; nevertheless the two genera 

 belong to the Conovulidse ; I have also ascertained that the C. 

 denticulatus beyond all doubt breathes free air; but I am not 

 quite so sure with respect to the P. bidentatus, though I believe 

 it is a pulmonifer. I am preparing a paper on the above species 

 as a supplement to that on the Conovulidse in the ' Annals/ 

 vol. vi. p. 447, n. s., see last paragraph, which, as this family has 

 created rhuch doubt as to its branchial dispositions, will I think 

 be acceptable to your readers. 



I have just fully observed the animal of the Chemnitzia Sand- 

 vicensis, which is an unrecorded desideratum. — Exmouth, May 

 24, 1851. 



XL VIII. — On the Tetrasporic Fruit of the genus Stenogramme. 



In a letter from Dr. C. Montagne to the Rev. M. J. Behkeley, 



M.A., F.L.S. 



"Paris, May 22, 1851. 

 " You are aware that a Floridea, collected first at Cadiz and pub- 

 lished by Agardh under the name of Delesseria interrupta, has 

 lately been found on the coast of England, of whose ' Nereis ' it is 

 certainly one of the most beautiful gems. This plant, whose 

 conceptacular fruit was scarcely known when I figured the species 

 in Webb's ' Otia Hispanica' (Pent. ii. p. 15. t. 8), from a single 

 specimen with rudimentary cpnceptacula, must be referred to the 

 new genus Stenogramme, founded more recently by Dr. Harvey 

 on an Alga gathered on the shores of California and those of 

 France near St. Jean de Luz. 



" But up to the present time, no specimen, whether from Spain, 

 England, France, or California, had exhibited tetraspores, or the 

 second form of fructification in this singular genus. It is to 

 Dr. Welwitsch, the learned botanist and Director of the Garden 

 at Lisbon, that we owe the discovery of the tetraspores, who has 

 sent me many individuals found in the Tagus near Lisbon, 

 together with three specimens bearing perfect conceptacula. 



" The tetraspores of Stenogramme interrupta are formed, as I was 

 the first to show in Gymnogongros Griffithsice (Hist. Nat. Canar, 

 Bot. Crypt, p. 160), in the endochromes of the radiating filaments 

 of the nemathecia which occupy the two surfaces of the frond. 

 These nemathecia are oblong, convex when moistened, but plane 

 and depressed when diy, and then distinguishable by the naked 

 eye only in consequence of the deeper tint of the portions of the 

 frond where they are situated. They are disposed with tolerable 

 regularity in two longitudinal hues, a few however being more or 

 less scattered. More rarely they are confluent, their length not 

 exceeding a line, and frequently not attaining that size. A proof 

 of their being simply a development into filaments or a multi- 



Ann. ^ Mag. N. Hist. Ser. 2.' Vol. vii. 31 



