MONOGRAPH OF THE EXISTING CKINOIDS. 641 



In 1884 Bell gi'eatly extended the known range of Ophiomaza cacaotica, record- 

 ing it from Suez and from Queensland. 



In 1888 Brock described as commensals on comatiilids O phiomasa cataphracta 

 from Cape York, and O phioa'thiops unicolor and Ophiosphcera insignis from Am- 

 boina. In 1895 Professor Kcehler described Ophioa'thiops elegans^ and in 1898 

 Ophiomaza mcerens. In the latter year Prof. Ludwig Doderlein described Ophio- 

 phthirius actinometroe . 



In 1904 Kcehler redescribed and revised Brock's species, but without discussing 

 their conunensalism. 



In 1908 H. C. Chadwick mentioned ophiurans, possibly Ophiomma cacaotica, 

 but more likely a species of Ophiacfk, on comatulids in the Red Sea ; and in 1915 

 Lieut. F. A. Potts published the results of his studies on the commensals living 

 on comatulids in Torres Strait, listing Ophlocoina, sp., Opklactis, sp. (later described 

 by Dr. H. L. Clark as O. delicata), Ophiomaza cacaotica, O. cacaotica var. picta, 

 and 0. obscura. 



Family TRICHASTERID^. 



The species of this family live upon arborescent marine organisms, and many 

 of them are quite active in their movements. Such of the species as live within 

 the range of the pentacrinites are undoubtedly occasionally to be found upon them. 



Family GORGONOCEPHALID^. 



Most, if not all, of the species of this family with undivided, or infrequently 

 divided, arms, and many of those with ramose arms, as Astrocynodus and Astro- 

 caneum, normally live attached to arborescent organisms. Such species as occur in 

 the regions inhabited by the pentacrinites may be expected occasionally to be found 

 upon them. 



ASTROGOIIPHUS VALLATUS LYMAN. 



This species is not uncommon on specimens of Isocrinus decorus taken off the 

 northern coast of Cuba. 



ASTEROrORPA ANNULATA LUTKEN. 



In 187.3 Wyville Thomson figured a specimen of laocnnus asteria to the cirri 

 of which was clinging an individual of this species. 



Family HEMIEURYALID^. 



The remarks under the preceding family heading apply equally to the species 

 of this family. Sigsieia murrhina Lyman has been found upon the species of 

 IsocHnus in the Caribbean Sea. The similarity in the tj^pe of coloration between 

 Sigsbeia Uneata Liitken and Mortensen and the echinoderms and crustaceans nor- 

 mally commensal on crinoids is striking. 



