364 Mr. P. W. Bassett-Smlth on 



short stout spines, which arc in places disposed in longitudinal 

 wavy lines. 



There is only a single specimen of this species ; it is 120 

 millim. in height and 140 in widtli, but the lower portion of 

 it was dead when dredged and the branches are hollowed out 

 by boring-sponges and incrusted by Nullipores. 



In its mode of groAvth and in the prominent lip of the calices 

 this form belongs to the same group as S. angulata, Kl., S. 

 jjacifica, Brugg., and >S'. spinjsa, M.-Edw. It approaches 

 nearest to 8. angulata, but the calices are much smaller and 

 closer arranged in the rows than in this species, and the 

 branches are less acuminate. 



There are in this specimen several instances of those pecu- 

 liar abnormalities of growth which Ehrenberg compared to 

 galls in plants. They assume the form of flattened hollow 

 disks, with thin walls formed of the coral ; the margins of 

 the disks are perforated. Imprisoned within each of these 

 discoid cages is a small crab which cannot escape. 



From tlie Tizard Bank, at a depth of | fath. 



Seriatopora compacta, sp. n. 



Corallum growing in small clumps consisting of rounded 

 or somewhat compressed branches about 6 millim. thick, which 

 dichotomize at intervals of from 5 to 7 millim. and frequently 

 coalesce, so that the coral has a fenestrate appearance. The 

 summit branchlets are short, from 3 to 5 millim., conical, 

 about 2 millim. thick at their bases, summits obtuse, 

 occasionally winged, crowded with young calices. Calices 

 closely arranged on branches ; the serial arrangement is not 

 distinct, but there appear to be about nine rows on a branch ; 

 the calices are from 2 to 3 millim. apart in the rows and 

 about an equal distance laterally ; there are from five to six 

 calices in a length of 5 millim. The calices are nearly 

 circular, from "6 to '75 millim. in width, their margins 

 scarcely at all prominent, but the upper lip is occasionally 

 indicated by longer spines. The calices are deep and the 

 large septa and the pits at the bottom can be distinguished. 

 The narrow interspaces between the calicos are covered witii 

 short spines. 



This species is of the type of S. crassa, Quelch, and S. 

 transversa, Quelch, but ditfcrs from these forms in having 

 less robust and closer arranged branches, whilst the calices 

 are lar<>cr and closer tojrother. 



Only two imperfect cxanij)les of this species have been 

 obtained ; the largest is 40 millim. in height by GO in width. 



Tizard Bank, of fath. 



