454 Verrill, Notes on Radiata. 



much smaller spicula. Possibly a large series of specimens might 

 show intermediate forms, but none occur in this collection. 



Primnoa Lamouroux. 



Primnoa Lamx., Polypiers flexibles, p. 440, 1816; Dana, Zooph., p. GTB; Edw. and 

 Haime, Corall., vol. i, p. 139; Kolliker, Icones Histiol., p. 135. 



Axis more or less calcareous, especially at the base, which is usually 

 quite stony. Verrucas usually in whorls, very prominent, covered 

 with scale-like, imbricated spicula. Coenenchyma also covered by 

 « smaller scale-like spicula. Type, P. reseda Pallas sp. [P. lepadifera 

 Lamx,). 



Primnoa compressa Verriu. 



Proceedings Essex Inst, vol. iv, p. 189, 1865. 



This species is, as yet, known only by its axis. It is much branched, 

 flabelliform. Tlie smaller branches arise alternately from each side of 

 the main branches, forming acute angles with them. Branches and 

 branchlets strongly compressed, delicately striated, hard and stony, 

 dark brown near the base, yellowish white and setaceous in the 

 branchlets. 



Height 24 inches ; diameter of largest branches '25. 



Aleutian Islands, — Capt. Gibson. 



Family, Briareidje Gray. 



Briaracees (section) Edw. and Haime, Coralliaires, vol. i, p. 188, 1857. 

 BriareidcB (family) Gray, Annals and Mag. Nat. Hist, vol. 4, p. 443, 1859. 

 Briaracece (family) Verrill, Memoirs Boston Society Nat Hist, 1, p. 10, 1863, 

 Briaridce (family) VerrUl, Proceedings Essex Institute, vol. iv, p 148, 1865. 

 Briareacece (sub-family) Kolliker, Icones Histiol., p. 141, 1865. 



Corallum arborescently branched, lobed, or encrusting foreign sub- 

 stances. Axis comj^osed of calcareous spicula, which are not consoli- 

 dated. Coenenchyma well developed, filled with small, rough spicula, 

 of various forms. Surface granulous. Cells scattered. 



The typical genera of this family are Priareum, Paragorgia, Titan- 

 ideum, and allied forms. These are usually arborescently branched, 

 or rise in irregular lobes, with a well marked spiculose axis. To these 

 typical genera Dr. Kolliker has added Sympodium and Erythropo- 

 dium, which are normally encrusting or parasitic species, with a thin- 

 ner coenenchyma and apparently without a distinct axis, and may, 

 perhaps, be best compared with the spreading basal portion of 

 Priareum. 



The position of the following genus seems doubtful, and though 

 agreeing best, in the structure of its spicula, with this family, it may 



