22 G. HERBERT FOWLER. 



iv. Memoirs referring to the Genus : — 

 Milne-Edwards and Haime, "Hist. Nat. des Coralliaires," iii., 164, 



pi. E i, Figs, la, lb. 

 Klunzinger, " Korallthiere des Kothen Meeres," ii. } 50. 



LOPHOHELIA PROLIFERA (FigS. 4-8). 



The material for a study of this form was entrusted to me by 

 Professor E. Eay Lankester, who had dredged it off Lervik, Stordoe, 

 Norway, and whom I am glad to be able thus to thank for his gene- 

 rosity. Owing to the great density of its corallum, and the consequent 

 damage to the tissues produced by prolonged decalcification in a 

 strongly acid medium, the work has been long delayed. Part of the 

 material had been placed directly in absolute alcohol ; part was 

 passed from corrosive sublimate through successive strengths of 

 spirit to 90 per cent, alcohol. Both sets were in excellent preserva- 

 tion, but the latter method appeared to be preferable, as resulting 

 in less shrinkage of the tissues. 



i. Corallum. — Of all corals this is probably the most generally 

 familiar, and requires here no systematic description. The theca, 

 which terminates the branches of the corallum, is solid, as in all 

 such Imperforata. The septa, which are exsert above the lip of the 

 theca, are both ectoccelic and entocoelic, but are only irregularly 

 arranged in orders. In a polyp with forty-eight septa, for instance, 

 of which twenty -four are ectoccelic, the remaining twenty -four 

 entoccelic septa are probably divisible into six primaries, six secon- 

 daries, and twelve tertiaries ; but, as they all are approximately of 

 the same length, this division is founded more on analogy than on 

 distinctive differences. The total number of septa, which probably 

 varies with the age of the individual polyp, is not necessarily a 

 multiple of six or twelve. 



Transverse sections of the corallum show, as has been recorded 

 for other forms, e.g., Cladocora (4), Caryophyllia (6), that a dark 

 line, indicating its earliest formed part, runs down the centre of each 

 septum, and may be termed a "centre of calcification." In addition 

 to these lines, however, sections, so made that they shall just cut 

 the extreme lip of the actual theca, exhibit other " centres of calci- 

 fication " between the enlarged ends of the septa, i.e., they lie in the 

 theca itself (Fig. 4). In sections at a lower plane the centres of 



