A. E\ Verrill — New Actinians. 143 



Art. XV. — Descriptions of imperfectly known and new 

 Actinians, with critical notes on other species, III ; by 

 A. E. Verrill. Brief Contributions to Zoology from the 

 Museum of Yale College, No. LX. 



Family Paractid^e Hertwig, op. cit., 1882. Andres, op. cit., p. 

 255, 1884. McMurrich, Proc. U. S. Nat, Mus., xvi, p. 160, 

 Jl., 1893. 



ParactidcB + Sideractidce Daniel., 1890. 



ParactidcB + Actinostolidce Carlgren, Kongl. Svenska. Akad. Handl., xxv, II, pp. 

 €4, 137, 1893. 



Entacmseous actinaria provided with a mesodermal sphincter 

 muscle, but destitute of acontia. Mesenteries usually numer- 

 ous, nearly always with 12 or more pairs perfect, the num- 

 ber and arrangement not always truly hexamerous. The 

 perfect and larger imperfect mesenteries are usually fertile. 

 Column-wall is usually smooth, sometimes with submarginal 

 plications and solid ridges ; rarely with low wart-like elevations 

 or small verrucse, sometimes capable of attaching sand, etc. 

 No actinobranchs. No acrorhagi. No disk-tubercles. 



The mesoglcea of the wall is usually tough and elastic, thin 

 or thick, often parchment-like or subfibrous, in deep sea forms 

 often thick and coriaceous. Base with an adhesive disk, which is 

 sometimes amplexicaul, embracing permanently the stems of 

 gorgonise 7 etc. Mouth with two siphonoglyphs and numerous 

 lateral folds. Tentacles simple, usually numerous and retrac- 

 tile. Margin generally capable of involution. 



This family appears likely to become an extensive one when 

 all the species, whose places in the system are still doubtful, 

 shall have been studied anatomically. At present there is no 

 practical and sure way to distinguish the Sagartiadce from this 

 family except by the presence of acontia in the latter, and 

 this is not always a satisfactory test* with preserved specimens. 

 However, the thin, smooth, tough, wall is often a fairly good 

 indication of this family, as is also the large number of perfect 



* All the acontia may be ejected and lost by violent contractions, when certain 

 SagarticB are placed in preservatives, or they may be easily decomposed in poorly 

 preserved specimens. So they are often not to be found in specimens known to 

 have had them in life. On this account it is doubtful whether several of the 

 genera described by Danielssen, 1890, as destitute of acontia, belong to Paractidct 

 or Sagartiadce. Of these Stelidiactis, Altantactis, Anthosactis, Kyathactis, and 

 Korenia are described as having pores or cinclides in the wall (the last has them 

 also in the disk). These genera may, therefore, be sagartians that have lost 

 their acontia. The first three have only 6 pairs of perfect and 'sterile mesen- 

 teries, as is often the case in Sagartiadce ; the fourth has 20 perfect pairs; the 

 last has 24 perfect pairs ; the base is amplexicaul. His Sideraciis is octamerous, 

 with 1 6 perfect pairs of very thin mesenteries, partly fertile ; tentacles not 

 retractile, 8 inner ones large; sphincter mesodermal. It probably belongs with 

 Paractidce. 



