OOSALLDTACRS. ' ( 1 



. much as Corallina differs from C. offici- 



nalis* Tii- generally kept up by all au- 



i, since the time of Ellis, who first distinguished it. 

 On the British shores it is mosl common on the southern 

 coast, while J. rubens is found all round the island. 



XLYI1I. HELOBESIA. 



152. polymorph* my-shaped Melobesid) ; frond at- 

 tached to rocks, thick, Btony, incrusting, or rising into 

 short, clumsy branches, which arc seldom much divided, and 

 often merely rudimentary ; eeramidia minute, depressed, ex- 

 tremely numerous, Harv. Jinn. ed. '1. p. 108. (Atlas, 

 PL XXXV. Fig. 157.) 



Millepora polymorpha, Linn. Nullipora polymorpha, Johnst. 

 9 ngites polymorpha, Ktz. CoraUium cretaceum licheno- 

 ides, Ellis. 

 Hal. On littoral rocks all round the coast, extending beyond 

 low-water mark. Common. 

 To this form I refer most of the lumpy Nulli] 

 with thick Btony fronds, and of various uncertain shapes, 

 found incrusting tidal rocks, and occasionally thrown up 

 or dredged from deeper water. Dr. Johnston's figu 

 Plate XXIV. 1, 2, 3, of his 'History of British S] 

 and Lithophytes,' represent a form which abounds in 

 Dalkey Sound near Dublin, and on which the late Mr. 

 M'Cafla founded a species which he called Nullipara 

 compressa. It perhaps ought to receive a specific name, 

 but, if left unennobled, it seems to me rather to fall, as a 

 variety, under M. calcarea, than under the present Bpecies. 



153. calcarea [The chalk Melohesia) ; frond unattached, Btony, 

 shrub-like, much branched; branches Blender, spreading in 

 all directions, cylindrical, anastomosing below, free above, and 

 tapering to a blunt point ; ramuli either simple or forked, 

 Harv. PL,,. Brit. pi. 291. (Atlas, PL \\\i\ . 



Nullipora calcarea, Johtut. X. fragilis, M'Calla. Spongitea 



calcarea, Kfz. Millepora calcarea. KU . ct . iSul. 

 Hah. South of England, and west of Scotland and Ireland. 

 On shingly or sandy shores, in 5-1 o fathoms water. Perennial. 

 This is one of the commonest of the British deep-water 



species of Melob ria t being found in many parts of the 



and generally in great abundance. It forms exten- 

 sive banks, on which the fronds are heaped together with- 

 out order, and appeal' to be kept from drifting merely by 

 their weight. The specimen.- at the top ot' the bank- are 



