Mrs. Thynne and Mr. Gosse on the Increase of Madrepores. 45Y 



then suddenly contracting it, they throw a stream three or four 

 inches from them, which falls slowly through the water to the 

 bottom of the glass bowl, where it looks like mist resting on the 

 glass. A few eggs are occasionally thrown out with it. One 

 would think they had some curious sympathy with each other, 

 that so many of them should be similarly engaged exactly at the 

 same moment. I find it mentioned in Dr. Johnston's * British 

 Zoophytes' that the ova of the Caryophyllia are discharged 

 through openings between the tentacula. My observation does 

 not confirm this, as I have frequently seen the eggs within the 

 tentacula so close as to be in masses ; but they have always been 

 expelled from them by retraction, and invariably escaped through 

 the mouth. The season for discharging the ova is betv/een 

 January and March. 



43. Of the adult Madrepores that I procured at Torquay six 

 years since, some have died, perhaps from the course of nature ; 

 but others have very much grown. They have enlarged their 

 polypi doms, and the tentacula are an inch long. 



44. May 2nd, 1852. — I have now 278 young Madrepores, 

 derived from those two mentioned April 11th, 1850; and they 

 are still subdividing so fast, that every day adds materially to 

 their number. A marble bath is the only " suitable accommo- 

 dation " (as house agents say) that I can think of for such a 

 rapidly increasing family. However, I am unable to see the 

 result, as I am obliged to leave the coast, and my thoughts and 

 leisure will be so entirely occupied with more serious duties, 

 that I cannot encumber myself with even a part of my flock. 

 I shall therefore commit my much-admired little favourites to the 

 ocean, in the sheltered and rocky cove of Waterwinch, and hope 

 they will form a colony on these shores. In future years, should 

 opportunity occur, I shall make a point of looking after them. 

 They have at present given no sign of forming a polypidom, 

 unless the white patches I have described can be considered an 

 indication ; and they are now two years old : but as my adults 

 have considerably enlarged and elongated their habitations under 

 the same treatment, I think I may conclude that the young 

 ones would have formed one also, had the natural period for so 

 doing arrived. 



45. The Madrepores thus appear to have three modes of re- 

 production : in the course of the first year, by spontaneous 

 fission ; during the second, by very frequent fission (every few 

 weeks), and by gemmules also ; and when adult, by ova. I am 

 not surprised at the rapid growth of the coral islands. 



46. It is very evident that the young Madrepores have not 

 arrived at maturity, though they are two years old, as the ten- 



