AlCTONAKIA. 363 ■ 



Bame as (i.), but with the tubejcles fewer and smaller at large 

 end. 



Hah. Port Darwin, N. coast of Australia, 7-12 fms. ; bottom sand 

 and mud. 



Obs. A young specimen of what appears to be this species is 

 almost white (in spirit). Several specimens preserved in spirit and 

 one dry (the latter probably from the same locality as the rest). The 

 serrated appearance imparted to the branches by the regularly 

 uniserial and rigidly lateral arrangement and the prominence of the 

 verrucse is the most striking external point distinguishing this 

 from other species of the genus. In spioulation, as in the external 

 characters of most young specimens, it approaches A. (MopseUa) 

 japonica, but has the tubercles of the large ends' of the cortical 

 fusiform spicules much less prominent, the spicules on the whole 

 smaller than in that species, in which, moreover, the small cortical 

 spicule is elongate, and has the whorls of tubercles at some distance 

 apart. Older specimens much resemble Mopsella textiformis in the 

 proportions and arrangement of the branches ; but the tint inclining 

 to crimson rather than to scarlet and the strictly marginal position 

 on them of most of the verrucse serve to distinguish A. serrata 

 superficially. The specimens are mostly more or less imperfect; 

 the tallest measures 80 miUim. in height. 



PSILACABARIA *, g. n. 



Melithseidse without " foliate spicules (Blattkeulen) ; branches 

 given off from soft joints at approximately right angles ; spicules 

 fusiform, the tubercles of the large cortical spicules tending to 

 coalesce into ring-like ridges ; verrucse spirally arranged. 



This genus is at once distinguished by the wide angles formed by 

 the branches ; those of other species of Melithaeidae rarely, if ever, 

 exceed 45°. ' The arrangement of the branches and of the -verrucae 

 upon them is less bilateraUy symmetrical than in any other Meli- 

 thaeid except Glaihraria ruhnnodis. Gray {Mopsella bicolor, Kolliker) ; 

 hence, perhaps, this is an older form, allied to the CoralliidEe or to 

 other Alcyonaria with imperfect bilateral symmetry. The ridge-like 

 tuberoulation of the larger cortical spicule is not elsewhere found, 

 though the smaller cortical spicule oiMelitodes oehracea has two similar 

 but usually continuous ring-like ridges. These spicules are unusually 

 large in the single species assigned to this genus ; in it, too, the 

 branches are remarkably slender and the internodes relatively very 

 long ; their pure white colour is a unique character among normal 

 adult specimens of known MelithaeaceEe ; although in the rare genera 

 Trinella and Parisis, which appear to me to be best ranked in this 

 family, as representing a distinct subfamily, the white colour re- 

 appears. This, however, is perhaps of superficial importance. In 

 all other respects it agrees with Acaharia, Gray. 



* Prom ^i\bs, slender, and Aoabaria a genus of Melithaidse (derivation 

 "Accabaar," Malay name of Melitodea oehracea). 



