120 Transactions of thi Society. 



SivJeria resembles Nidalia, but the Nidalia colony is uuliranched, 

 and there are many other differences apart from Studeria's retractile 

 polvparium. In certain respects, e.g. in its huge spindles and in 

 the finger-like lobes densely covered \rith polyps, Studeria resembles 

 a form like Sckrophi/fum poli/dactylvm, but the polyp? are quite 

 different iu the two, and there is not in Studeria any hint of dimor- 

 phism. The non-retractUe calyces, the mode of brandling, the 

 nature of the spiculation, and other features separate Studeria 

 from Alci/onium and several nearly related genera. So we might 

 review all the genera of Alcyoniidte, but to little profit, for there 

 is only one which can be thought of as having close affinities 

 witli our new type. That one is the genus Pffm/cyo;H*'/», estab- 

 lished by Milne-Edwards. Milne-Edwards gave the following 

 diagnosis of Paredviimiium, : " Polyparium of a coriaceous tissue 

 towards the base and there forming a cylindrical tube with spicu- 

 lose walls, into the interior of wldch all the upper and soft part of 

 the polyparium, including the polyps themselves, can lie completely 

 retracted.""* 



In his original description oi Paralci/onium, when he called it 

 Alcyonide,t Iklilne-Edwards gave a number of interesting details. 

 He distinguished a brown firm "foot" fixed by its base, and a 

 white, delicate, branched trunk ynth twigs ending in small polyiis. 

 The ca-sdties of the polyps unite in forming longitudinal canals 

 which are continued to the base, those which lie to the outside 

 having theii- walls strengthened by numerous brown spindles. 

 Ova are developed on lameUre in the lower part of the canals of 

 the trunk and fall into the cavity, accumulating further down. 

 On the polyps there are, according to Milne-Edwards, rows of 

 " spicules cartilagineuses brunatres." 



"Wright and Studer gave the following definition of Paralcy- 

 oiiium in the ' Challenger ' lieport on Alcyonarians (1889) : — " The 

 colony presents two distinct portions : one, the ftasal portion, is 

 dense, with firm walls; the other, the head, alone bears the 

 polyps, and can be in part withdrawn into the basal part. The 

 polyp-bearing portion is but feebly lobed." In his " Yersuch eines 

 Systemes der Alcyonaria '' t Studer had suggested affinity with 

 Nidalia. 



Our new type Studeria agrees with Parcdcyonium (1) in having 

 the polyp-bearing portion retractile into the basal portion, (2) in 

 the disposition of the longitudinal canals, and (3) in having verj- 

 large fusiform spicules. But there the resemblance stops, and 

 there can be no question as to the lUstinctiveness of the two very- 

 remarkable genera. 



» Histoire Naturelle des Coralliaiies, 1S57, p. 129. 

 + Ann, Sci. Nat., ser. 2, iv. (1835) pp. 323-33 (9 figs.). 

 X Arch. Natur., liii. (1887). 



