On the ^ Porciqnne ^-Expedition Madrcporaria. 293 



Notwithstanding the temperature in which the corals were found, 

 nud the deptli of the sea, they are strong and well- developed forms, 

 evidencing an active and abundant nutrition. 



There is no diiHculty in classifying the specimens with tlio Theco- 

 jisumviiie of I'ourtales. 



The^opsammla sonalis, Pourtales, was dredged up in from 100 to 

 30n fathoms, off Sombrero, near Florida, in the course of the (julf- 

 stream. 



I have been able to compare the specimens dredged np in the 

 * Porcupine' Expedition with ^. I'ourtales's types, and, after making 

 due allowance for variation, I have no doubt about including the 

 British forms under his specific term. These varieties of the Flo- 

 ridan type, found at greater depths, and doubtless in much colder 

 water, present evidences of greater vigour than the American forms. 

 They are larger and denser, and their septa are better developed. 

 Moreover some of them, although they possess all the other charac- 

 teristics of the genus as diagnosed by Pourtales, present indubitable 

 costa?, especially interiorly. This clinging to the Ealanophyllian 

 tj'pe is not witnessed in the Ploridan forms ; but it is too important 

 to be passed over, especially as it renders the generic distinction 

 between many wcli-knowa Balanophyll ia' and the new 2'hecopsammice 

 very unstable. The Thecopsammia', from the peculiarities of their 

 wall, epitheca, and septa, well merit the distinction of a subgenus ; 

 and therefore I propose to restore the species associated under the 

 term to the genus BalanophylUa, in the subgenus Thecopsammia. 



BulanophjlJia {Thecopsammia) soclalis, Pourtales, var. cosiata. No. 

 oi, ' Porcupine ' Expedition. 



( ) , var. britannica. No. 54, 'Porcupine' Expedi- 

 tion. 



( ) , var. Jeffrey ski. No. Go. 



All these varieties refer to specimens wliich were fixed by their 

 bases to stones. 



The varieties and the original types are very isolated forms in the 

 great genus BalanoplijUla. They have only a very remote afiinity 

 with tlie "West-Indian recent BalanophyUkv, with those of the Crag, 

 the Faluns, and the Eastern Tertiaries. 



The British forms appear to have emi grated from the south-west ; 

 nnd probably the original type wandered through the agency of tho 

 Gulf-stream, which carried the ova and deposited them in our north- 

 ern sea, where they have propagated, varied, and thriven. 



PUobothrus s)/mmetrieus, Pourtales. — A specimen of this doubtful 

 coral (which had been described by M. de Pourtales from the results 

 of dredging in from 100 to 2(H) fathoms) was sent to me by Dr. Car- 

 penter. It came from the cold area, in from 500 to GOO fathoms. 



There is no doubt that this very polyzoic-looking mass belongs to 

 the American type. The tabulie are hardlj- worthy to be called such ; 

 and I place the form amongst the Z nintharia provisionally. 



III. The species of Madreporarta belong to genera Avhich do not 

 contribute and have not contributed to form coral-reef faunas. None 



