306 



THE VOYAGE OF H.M.S. CHALLENGER. 



2. Pentacnnus mulleri, Oersted, 1856 (Pis. XIV., XV.; PI. XVII. figs. 9, 10). 



1821. Pentacrinus capuf-Medusie, MiUer (pars), A Natural History of the Crinoidea, p. 46. 

 1813. Pentacrums capiit-Medusce, Miiller (pars), Abhandl. d. k. Akad. d. Wiss. Berlin, 1843, p. 185. 

 1845. Pentacnnus Capuf-Medusce, Austin (pars), A IMonograph of Eecent and Fossil Crinoidea, p. 111. 

 1856. Pentacrinus Mulleri, Oersted, Forhandl. Skand. Naturf., 1^' Mode i Christiania, 1856, p. 202. 



1864. Pentacrinus Miilleri, Liitken, Yidensk. Meddel. f. d. nat. Foren. i Kjobenhavn, 1864, Nr. 13-16, p. 207. 



1865. Pentacrinus (Neocriniis) Miilleri, Wyville Thomson, Phil. Trans., 1865, vol. civ. p. 542. 

 1882. Pentacrinus miilleri, P. H. Carpenter, Bull. INIus. Comp. Zobl., vol. x.. No. 4, p. 170. 



non Pentacrimis Miilleri, WyviUe Thomson, in Proc. Koy. See. Edin., vol. vii. p. 776 ; and in The 



Depths of the Sea, p. 442. 

 non Pentacrinus Miilleri, Agassiz and Pourtales, in Bull. Mus. Comp. Zoijl., vols, v., vi. 



Dimensions. 



Total lengtli of largest specimen,^ 



Greatest length of entire stem, rounded off at sixteenth node, 



Shortest stem, rounded off at twelfth node, 



Diameter of stem, .... 



Longest cirrus (forty-three joints), 



Diameter of calyx, .... 



Diameter of disk, .... 



Length of arm (one hundred joints), 



Length of pinnule on first free brachial (fifteen joints). 



Length of pinnule from middle of arm (twenty-one joints). 



Stem robust, but of no great length. Outline pentagonal, with rounded angles and 

 smooth surface. Internodal joints four to eleven (usually six to eight) in number, with 

 but slightly crenulated edges, even in the upper part of the stem. Cirrus-sockets trans- 

 versely oval and not reaching the upper edges of the nodal joints, but extending more or 

 less downwards on to the infra-nodals, which are grooved to receive the cirrus-bases. 



Cirri composed of thirty to forty-five stout, smooth, and tolerabl}^ equal joints, the 

 later ones of which may have a couple of small, blunt projections on the ventral side. 

 Terminal claw small and without an opposing spine. Lowest limit of the interarticular 

 pores between the fourth and eighth nodes. 



Basals variable ; sometimes pentagonal, forming a closed ring ; sometimes triangular 

 or rhomboidal, barely in contact })y their lower angles ; and sometimes c^uite small, not 

 meeting at all upon the exterior of the calyx. Pays and their subdivisions not separated 

 by perisome, but in close lateral contact, the joints as far as the lowest free brachials 

 beyond the tertiary axillaries having their sides more or less flattened, often very much 

 so. The two outer radials united by syzygy. There are usually six or eight arms on 



1 The total length of this individual, which was obtained by Captain Cole, and is now in the Natural History Museum, 

 is slightly greater than that of the largest specimen dredged by the " Blake." The stem, which is 19 cm. long, is broken 

 just below the twenty-first node. But in the same bottle there is a fragment which appears to be the bottom part of 

 this stem, and has the lowest nodal joint closed in the usual way. 



