386 Veriull, N'otes on Had lata. 



with a slender axis, smooth in the middle, but surrounded toward 

 each end with a circular and usually sharp ridge, like a little wheel. 

 These spicula are often broader than long, and then, when seen end- 

 wise, resemble disks or circular beads with an apparent depression or 

 perforation at the centre, owing to the transparency of the axis. In 

 addition to the six species described below, this group iucludes G. 

 fusco-purpurea Kolliker, the spicula of which he has well figured (Taf. 

 xviii, figs. 28-31), and perhaps other described species. {Eugorgia V.). 



In each of these two groups there are species with virgate, pinnate, 

 bipinnate, and reticulated branches. There are also, in each, species 

 with flat and with prominent cells. It is therefore evident that such ex- 

 ternal chai-acters as the mode of branching and degree of prominence 

 of the cells, cannot be considered as of generic importance, and that 

 such genera as TlhipidogoTgla Yal. and T^eptogorgia Edw., founded 

 only on such characters, are unnatural and heterogeneous groups, 

 which should be dropped from our system of classification. 



It is probable, however, that more than the two natural groups 

 above described, are included in the first of Dr. Kolliker's sections, 

 represented by species that I have not been able to study satisfacto- 

 rily, and among those groups that are most likely to prove distinct 

 types, is that embracing G. pjolma and allied species, corresponding 

 partly to the genus Lophogorgia Edw. and Haime. 



The species of Gorgoninae which I have been able to study, may 

 be arranged, in accordance with the above considerations, in the fol- 

 lowing manner : 



Gorgouia. — Species having sjjindles in the coeuenchyma, and an 

 external layer of peculiar, small, club-shaped spicula, producing a 

 smooth surface. Type, G. verrucosa \^.^ [now EunicellaY. — Reprint). 



Pterogorgia. — Species having in the coeuenchyma small double- 

 spindles and also crescent or bracket-shaped spicula, nearly smooth 

 on tlie convex side. Type, P. acerosa Ehr. (now Gorgonia. — Reprint). 



Eugorgia. — 'Species having longer and shorter double-spindles, and 

 numerous double-wheels; surface decidedly granulous, with naked 

 spicula. Type, E. ampla V. 



* It is not improbable that upon further study this group wUl be found to belong to 

 the Plexauridce, near Uunicea, with which Ehrenberg, indeed, united it. So far as my 

 examinations have gone this appears to me to be more in accordance with its true affin- 

 ities. If this suggestion prove correct, the group should receive a new generic name, 

 and Gorgonia should be restricted, partially in accordance with Ehrenberg's work, to 

 the second group (now Pterojorgla) with G. flahsllum as its type, and including, also, 

 the true Pterogorgim ; and in fact these are also the most common and well-known 

 LmnjEan species. (Later studies ha\-ing confirmed this view, I have since adopted it, 

 in Am. Jour. Sci., xlviii, p. Nov., 1869. — Reprint). 



