38 



la cellule fécondatrice vient porter par des éléments distincts , sur la 

 partie fondamentale de l'œuf, le cytoplasme et sur son organe le plus 

 important, le noyau. On ne saurait admettre que les phénomènes 

 nucléaires qui se produisent au moment de la fécondation, constituent 

 l'essence de ce phénomène, et on ne saurait voir dans le noyau ou dans 

 une portion de la substance nucléaire, la chromatine, le substratum 

 unique des caractères essentiels de l'individu. 



2. Note on the structure and systematic position of 

 Lebrunia neglecta, Duch. and Mich. 



By Professor J. Playfair Me. Murr ich. 



ehigeg. 10. November 1888. 



I have recently been enabled, through the kindness of my friend 

 Dr. C. S. Dolley, to study a specimen of the singular Lehrunia 

 iieglecta, which was originally described in 1860 by MM. Duchas- 

 saing and Mich elotti i, and since that time has not apparently 

 come under the observation of any student of the Actiniaria. It is a 

 somewhat low form, measuring about 2,9 cm in height, and about the 

 same in diameter, though the determination of this latter measurement 

 in the living animal is rather difficult owing to the column being con- 

 tinually hidden by the tentacles which hang down over it so that their 

 tips rest on the rock to which the animal is attached. Its most impor- 

 tant peculiarity consists in the possession of six — not five as Du- 

 chassaing and Michelotti describe — dichotomously branched 

 processes, arising from the column wall immediately below the margin. 

 These pseudo-tentacles, to adopt a term proposed by R. Hertwig, 

 are hollow outgrowths of the column wall, and each consist of a some- 

 what elongated cylindrical basal portion, measuring 3,8 cm in length 

 by 0,8 cm in diameter. This divides into two equal branches, which 

 again dichotomize several times, producing a dendritic structure. 

 Transverse sections through the basal portion show a histological simi- 

 larity to the column wall, but the longitudinal endodermal muscles 

 are peculiar in being arranged in bands, the intervals between these 

 being entirely destitute of muscle cells. In the terminal branches the 

 ectoderm becomes loaded with nematocysts which are absent in sections 

 lower down. The tentacles are apparently 11)2 in number, and are ar- 

 ranged in six cycles; they are marginal in position. The mesenteries 

 are quite numerous, there l)eing probably a pair corresi)onding to 



• P. Duchaaaainp; et J. Michelotti, Mémoire sur les Coralliaircs des An- 

 tilles. Mem. llcale Accad. di Torino. Sér. 2«lo. T. XIX. 1860. 



