REPORT ON THE ALCYONARIA. 147 



white branches. The enlarged figure of a polyp represents a thin central horny axis with 

 a rather thick coenenchyma and a semi-retracted polyp, possibly a Muriceid. 



The enlarged figure given of Swiftia exserta, D. and M. {loc. cit., pi. xi. fig. 5), shows 

 a thin coenenchyma with a thick axis, and we read " Nous ne donnons ])as la description 

 dc cette espece, qui a dejJi, ete publiee par les auteurs." Good specimens of Thesea 

 guadalupensis, D. and M., are still in the Museum at Turin, and this form would appear 

 to be near Acis, D. and M. The axis is horn}', not effervescing with acids ; polyjis 

 prominent, and the coenenchyma is loaded with very large irregular spicules. 



A new species of Thesea has been described by Verrill,* Thesea gemmata, which the 

 author says rescmljlcs in external characters Gorgonia exserta as figured by Ellis and 

 Solander, which latter Du(;hassaing and Michelotti refer to t\ie.\v Swiftia exserta, but it has 

 more prominent verrucse. Its spicules are however very difierent from those of Thesea 

 guadalupensis,!). and M. The Gorgonia richardii, D. andM., bears some resemblance 

 to it in external appearance, so far as one can judge from the figures, but has stouter 

 branches and more cylindrical verrucse. 



It seems desirable to mention these facts here, for Thesea gemmata, Vcrrill, appears 

 to have a likeness to a very interesting species of Gorgonid found by the Challenger 

 Expedition at Banda, for which we have been obliged to make the above new genus, 

 Verrill's sj)ecies was obtained in deep water off St. Croix, West Indies. 



Platycaulos danielsseni, n. sp. (PL XXXIII. fig. 8 ; PI. XXXV. figs. 1, lo). 



The colony is branched, the branches arising in the one plane ; both the stem and 

 branches are compressed. The total height of the colony is 325 mm., with a basal axial 

 diameter of 8 mm. in its broad and of 4 mm. in its short diameter. The colony was 

 attached by a broad base, the remains of which are preserved. The branches rise at 

 intervals of about 10 mm., at a height of 9.5 mm. from the base the broad diameter of the 

 axis is G mm. The first six l)ranches from the left side of the stem arc short, from 15 to 

 20 mm. in length, simple or feebly branched. The seventh extends to a length of 1 70 mm. 

 with a breadth of 5 mm., and divides into a number of smaller branches which again divide ; 

 between two of these there is an anastomosis. At an interval of 50 mm. another large 

 branch is given off, which also divides as in the former case ; between the two large 

 branches and between the second branch and the apex of the stem there are several 

 small twigs ; the lengths of these diminish as they approach the summit. The ramification 

 of the left side of the stem is of the same nature, but all the branches are smaller than 

 those of the opposite side, not exceeding 130 mm. in length. One of the smaller 

 branches has become anastomosed with the main axis. Tiie cauieuchyma is moderate in 

 tliickness, when dry it presents a roughened appearance owing to an outer layer of spiny 

 spindle-shaped spicules ; an inner layer contains ^oth stellate and spindle-shaped spicules. 



' Amer. Journ. Sci. and Arts, vol. .\lyiii. p. 428. 



