330 ESCHARID^. 



of course the mouth is sunk below the surface. In few 

 cases is the appearance of a species so completely changed 

 by age and the progress of calcification (Plate XXXIX. 

 % 5). 



HABITAT. On stones, and PoreUa compressa, from deep 

 water. 



LOCALITY. " About 25 miles north of the island of 

 Unst, the most northern of the Shetland group," very 

 rare (A. M. N.). 



GEOGRAPHICAL DISTRIBUTION. Bergen (A. M. N.) : 

 lat. 73 41' 6", long. 22 58' 30", in 220 fathoms (Dutch 

 Arctic Exped.) . 



I have no hesitation in referring this species to the 

 genus Porella. It is closely allied to P. concinna; it 

 presents the very marked shape of the mouth, slightly 

 modified in its proportions, which is characteristic of that 

 species, while at the same time there is a complete paral- 

 lelism between the two forms in the mode in which the 

 orifice is developed. 



c. Zoarium erect ; branches compressed. 



PORELLA COMPRESSA, Sowerby. 

 Plate XLV. figs. 4-7 ; woodcut, fig. 14. 



Poaus CERVINUS, Borlase, N. Hist. Cornwall, 240, pi. xxiv. fig. 7. 



MILLEPORA COMPRESSA, Sowerby, Brit. Miscel. i. (1806), 83, pi. xli. 



CELLEPORA CERVICORNIS, Flem. Br. An. 532: Johnston, B. Z. ed. 2, 298, 

 pi. liii. (fide Alder, who had examined the type specimen in 

 the British Museum): Couch, Corn. Faun. pt. iii. Ill, 

 pi. ix. fig. 1 : Busk, Ann. N. H. ser. 2, xviii. 32, pi. i. fig. 1: 

 -Sara, Reise Lof. Finm., N. Mag. f. Naturv. vi. 147 (27 sep.): 

 Alder, Quart. Journ. Micr. So. n. s. iv. (1864), 98. 



ESCHARA CERVICORNIS, Busk, B.M. Cat. ii. 92, pi. cix. fig. 7, cxix. fig. 1 : 

 D'Orbigny, Pal. Fran9. I. c. 344: Hincka, Devon Cat, Ann. 



