106 



THE VOYAGE OF H.M.S. CHALLENGER. 



contained in a thickened portion of the transverse mesenteries. In Antipathella sub- 

 pinnata the cellular elements of the ectoderm are arranged differently to those in 

 Antipathes dichotoma, the clusters of nematocysts, in sections, being usually situated in 

 depressions, instead of in the centre of prominent crenations. 



The corallum may be laxly branched with all its subdivisions free, or it may become 

 fan-like, extending chiefly in one plane, in which case the lower portions are always con- 

 fluent, whilst the upper and terminal ones may be completely fused together or free 

 towards the apex. The spines are usually short, triangular, or conical, but, in Antipathella 

 subpinnata, they become elongate and slender on the stronger branches and branchlets. 



Synopsis of Species. 



A. Corallum laxly branched, pinnules usually simple, with or without fusion of parts. 



1 . Pinnules short, distant, free, not all in one plane ; spines triangular at first, 



becoming conical and ultimately needle-like, .... 



2. Corallum laxly branched, pinnules on all sides, elongate, very slender and 



free ; spines triangular, rather numerous, not in a spiral, 



3. Corallum laxly branched, branches with four irregular rows of short 



slender pinnules, which are rather distant ; spines strong and distant, 

 arranged in unequal sinistrorse spirals, ..... 



4. Corallum branched, with slender paniculate branches, presenting frequent 



fusions and approaching the characters of section B of this genus ; 

 branchlets not all in a plane ; spines conical, unequal, disposed in 

 irregular sinistrorse spirals, ...... 



B. Corallum extending chiefly in one plane ; branches confluent, paniculate. 



o. Terminal fronds free. 



1. Whole corallum small and very delicate ; spines close-set, short, trian- 



gular, compressed, ....... 



2. Terminal fronds delicate; spines conical, short, not in a spiral, 



3. Terminal fronds delicate ; spines conical, short, arranged in open sinistrorse 



spirals, ........ 



4. Terminal fronds strong, tapering ; spines short, triangular (1), arranged in 



verticils, ........ 



/3. Terminal fronds fused together. 



5. Fronds elongate and narrow ; spines conical, pointed, arranged in spirals, 



6. Fronds broader, but of same type as in sp. 5 ; spines elongate, conical, not 



in distinct spirals, ....... 



7. Fronds very broad, delicate ; branchlets straight, but otherwise similar 



to those of sp. 8 ; spines very numerous and irregular on the pinnules, 

 very thick with a blunt apex, ...... 



8. Fronds broad, delicate, reticulum close, ultimate pinnules setose ; spines 



more elongate, slender, with a sharp apex, .... 



C. Corallum flattened, but with pinnules not in a plane. 



1. Corallum dense and irregular, the strong portions forming a coarse 

 reticulum ; pinnules very slender, simple, pinnate, or bipinnate, 

 radiating in all directions ; spines short, triangular, ' . 



subpinnata (E. and S.). 

 strigosa, n. sp. 



intemiedia, n. sp. 

 boscii (Lamx.). 



tristis (Duch.). 

 gracilis (Gray). 



atlantica (Gray). 



paniculata (Duch. and 



Mich.). 

 minor, n. sp. 



spieciosa, n. sp. 



assimilis, n. sp. 

 reticulata (Esp.). 



contorta, n. sp. 



