456 Mrs. Thynne and Mr. Gosse on the Increase of Madrepores. 



34. August 18th. — One of the gemmules has divided into 

 two parts; one half has separated from the parent, and has 

 twenty-five tentacula, and the mouth on one side, as wlien the 

 older ones divide ; the other half remains attached to the mother. 



35. September 1st. — Another gemmule has disengaged itself 

 from the parent. In this instance it has left no twin brother 

 behind. It has thirty-four tentacula fully developed, and there 

 are white spots where others are coming. 



36. September 16th. — Another gemma. The little speck of a 

 Madrepore composed entirely of new growth, which 1 described 

 June 25th, has grown to the size of a fourpenny piece, and has 

 just subdivided again into four. 



37. October 11th. — The gemmule described as separating 

 from the parent (Sept. 1st) has subdivided into two parts. 



38. October 19th. — My little flock increases daily. I have 

 now eighty-three Madrepores, seven of which are gemmules. 

 The gemmules resemble the others in a very short time. I know 

 them apart only from their situations. I shall be curious to see 

 whether they become fixtures at the same time. 



39. October 24th. — The half of the gemmule mentioned 

 (August 18th) as remaining attached to the parent has separated 

 from it. 



40. December 7th. — The half of the gemmule which sepa- 

 rated from the parent (August 18th) is now dividing into three. 

 The other half, which detached itself October 24th, is at the 

 same time dividing into two. Therefore this first gemmnle, 

 which I discovered June 27th, has now multiplied into five. 



41. In looking over my Notes, I find I have omitted to men- 

 tion an appearance peculiar to the young Madrepores : they 

 have, all of them more or less, between the several rows of ten- 

 tacula and the mouth, patches of a milk-white fluid or substance ; 

 it first appears in minute specks, which by multiplying or uniting 

 form variously shaped patches, in some cases almost cover- 

 ing the entire space between the several rows of tentacula and 

 the mouth, and in others forming a broken or sometimes con- 

 nected ring, of uneven width, just within the tentacula. In 

 many of them it is so dense that it looks quite like chalk. After 

 fission, the new part is at first without it, but it soon appears. 

 The gemmules also have it very early. Can this be the mate- 

 rial for the future polypidom ? All my young Madi'epores have 

 four circles of tentacula. 



42. Feb. 18th, 1852. — During the day, seven of my adult 

 Madrepores have at intervals been ejecting a whitish-blue fluid, 

 resembling wood-smoke*. By first elevating the mouth and 



* This was doiibtless the spermatic fluid of the males. Sec mv ' Aetino- 

 logia Britannica,' pp. 99 and 100. — P. H. G. 



