122 



THE VOYAGE OF H.M.S. CHALLENGEE. 



so that their true position is still uncertain. A number of others, of which the polyps 

 are not known, are also temporarily included, solely from a comparison of their skeletal 

 characters. 



sarothamnoides, n. sp. 

 salix (Pourt.). 



fruticosa (Gray). 

 verticillata, n. sp. 



Synopsis of Species. 



Section I. — Corallum shrub-like, not in one plane, without any regular fusion of parts, 

 but occasionally a few of the branches may be adherent. 



A. Spines subequal, not longer in the neighbourhood of the polyps. 



a. Branches spreading, virgate, without slender pinnules. 



1. Corallum laxly and irregularly branched, like a spray of broom; branch- 



lets relatively thick ; spines very long and closely set, 



2. Corallum irregularly branched, with long, slender, drooping pinnules; 



spines thorndike in irregular longitudinal rows, 



3. Corallum laxly flabellate, flattened ; branchlets long and slender; pinnules 



all on one side ; spines of two very distinct sizes, the smaller regularly 

 distributed between the larger, ..... 



4. Corallum allied to that of Aplianipathes fruticosa, in mode of branching ; 



spines arranged in verticils, and covered with sharp spinose processes, . 



5. Branchlets long and straight, chiefly in one plane and collected into fan- 



like groups, simple, or bearing two or three secondary branchlets ; 

 spines rough, with a blunt apex, ..... 



/?. Branches bearing two or more rows of slender pinnules. 



6. Stem branched; branchlets bearing two lateral alternate rows of closely-set 



pinnules, certain of which become elongate and pinnate; spines elongate, 

 broad and flattened, arranged in close dextrorse spirals, 



7. Stem simple, short, bearing relatively long, alternate, simple, closely set 



pinnules; spines acicular, in irregular longitudinal rows, 



8. Stem branched, branches collected into groups, bearing four rows of 



pinnules, two lateral and relatively close, others from antero-lateral 

 margins, irregular and more distant ; spines rough, arranged in irregular 

 dextrorse spirals, ....... 



9. Stem branched, branches bearing slender pinnules arranged spirally ; 



spines simple, tapering to a slender point, arranged in steep irregular 

 dextrorse spirals, ....... 



10. Stem simple ; branchlets in five equidistant, subhorizontal rows, lower 

 ones bearing one or two simple or forked processes near the base ; spines 

 broad and much flattened, ...... 



B. Spines longer about the polyps, giving an appearance of successive swellings on 



the axis. 



Corallum subflabellate ; spines exceedingly long and numerous, forming 

 dense moniliform dilations of the axis in the region of each zooid, 



Corallum densely flabellate, branches without regular pinnate arrange- 

 ment; spines rather short, excejating a few in the neighbourhood of each 

 zooid, which are long and slender, ..... 



Branches regularly pinnate; pinnules lateral, nearly at right angles, 

 short, with spinose processes ; longer spines slightly rugose, 



pedata (Gray). 



pennacea (Pall.). 

 eupteridea (Lamx.). 



alcda, n. sp. 

 wollastoni (Gray, MS.). 

 barhadenxis, n. sp. 



humilis (Pourt.). 



thyroides (Pourt.). 

 filix (Pourt.). 



