Family Muriceid.e Verrill. 



j^Iitricfa Lamouroux, Exposition Methodique, 1821, p. 36. 



Muricea Milne Edwards and Haime, Histoire naturelle des Coralliaires, 1857, Vol. I, p. 142. 



Muriceadce Studer, Monatsber. d. k. preuss. Akad. d. Wiss., Berlin, 1878, p. 641. 



Miiriceidce Verrill, Bull. Mus. Comp. Zool., XI, N" i, 1883, p. 30. 



Muriceida Wright and Studer, Challenger report, Alcyonaria, 1889, p. 92. 



Mnriceidie Hiles, Gorgonacea collected by Dr. WiLLEY, 1899, p. 197. 



Muriceidti: Bourne, Treatise on Zoology, Part II, Anthozoa, 1900, p. 28. 



MuriceidcB Hickson, Cambridge Natural History, Vol. I, 1906, p. 355. 



Axis cylinder horny, not divided into segments; water-vascular canals not in a regular 

 series arranged around the axis; calyces of various shapes, but never with their margins turned 

 towards the branch or stem. A pseudo-operculum is almost always present consisting of spicules 

 borne on the dorsal surfaces of the tentacles; there being eight segments to the operculum, 

 each segment usually consisting of three spindles which form an acute-angled triangle with its 

 apex directed towards the centre of the mass of infolded tentacles. A well-marked collaret lies 

 below the operculum, and consists of one or more transverse rows of spindles. The spicules 

 vary exceedingly in size and pattern, but are never in the fcjrm of greatly flattened scales 

 with radiating costa; produced into marginal points. The coenenchyma usually has a bristling 

 appearance, due to the projecting points of spicules. 



This family seems to be a fairly natural one; but it intergrades on the one hand with 

 the Primnoidse, and on the other with the Plexauridae. It differs from the former in not having 

 a true operculum emplanted on the calyx margin, but instead, has a pseudo-operculum of eight 

 segments, each segment being composed of several spicules, instead of one as in the Primnoidce. 

 There is an approach to the primnoid type of spicule in some of the scale-like plates of 

 Placogorgia^ but without radiating costa;. 



The relationship of the Ahiriceidcp seems closest with the Plcxaiirida-, the superficial 

 resemblance being such as to deceive any one, especially as in such species as Placogorgia 

 cryptothcca which greatly resembles Plexauroides not only in general appearance, but also in 

 form and arrangement of spicules. 



The main difference between the two families is shown by a study of a cross section of 

 the stem. In a ])lexaund such a .section will reveal a thick coenenchyma enveloping the axis; 

 while around the latter is a symmetrical series of distinct round or oval openings, .sections of the 

 primary water-vascular canals. In a muriceid a similar section would show a thinner ccenenchyma, 

 and no regular series of canals, these being irregular both in section and disposition. 



