PKIMNOAD^. 43 



Fam. 18. PRIMNOADiE. 



Coral simple or branched ; branches forked or pinnate. The axis 

 continuous, inarticulate, solid, containing a large portion of carbo- 

 nate of lime, especially towards the base, where it is stony, but 

 horn-like at the smaller branches. Bark formed of imbricate cal- 

 careous plates, without any distinct lateral groove or smooth 

 lateral space. Polype-ceUs bent down on all sides of the branches, 

 often arranged in whorls, very prominent, covered with imbricate 

 scale-like spicules, usually smoother at the narrow base. 



Primnoacea (part.), Milne-Ediv. Corall. i. p, 138; Verrill, Mem. Boston 

 Sac. Nat. Hist. 1862, i. p. 9 ; Kdlliker, Ic. Hist. p. 135. 



PrimnoadEe, Gray, P. Z. S. 1857, p. 285, 1859, p. 483 ; Ann. ^ Mag. 

 Nat. Hist. 1859, iv. p. 442. 



Primnoa, Lamx. Polyp. Flex. p. 440 ; Milne-Echo. (§- Haime, Corall. i. 

 p. 139. 



A. Polype-cells ovate, peduncled, large, scattered or in whorls on 

 the branches. 



1. Peimnoa. Coral tree-like, dichotomous. CeUs ovate, beU-shaped, 



in threes. 



2. Thotjaeella. Coral bottlebrush-shaped ; branches subsimple. 



Cells ovate, solitary on the upperside of the branches. 



3. Chkysogokgia. Coral cylindrical, furcately branched. CeUs bell- 



shaped, sessile, scattered on the sides of the branches. 



4. Fanellia. Coral fan-shaped, branches and bran chlets compressed 



on a plane. CeUs ? 



5. RnsEA. Coral branched, paniculate. CeUs beU-shaped, largely 



pediceUed, racemose. 



6. Mytjra. Coral simple. CeUs ovate, in series on the sides of the 



stem. 



B. Polype-cells tubercular, on the sides of the branches. 



7. SwiFTiA. Coral branched, furcate. CeUs conical, truncate, in two 



alternating series. 



8. Thesea. Coral branched, branches slender. CeUs subalternate. 



C. Polype-ceUs cylindnad or clavate, diverging, in two lateral 

 series on the branches. 



9. Steneha. 



