ON COLOURING MATTERS OF VARIOUS ANIMALS. 5 



a mottled yellow and broAvn colour. The pink colouring 

 matter in the fresh condition yielded a single well-marked 

 absorption band (PL 1, fig. 4). The coloming matter when 

 dried retained its spectrum. It was insoluble in absolute 

 alcohol. The filaments emitted from the pores in the body- 

 Avall of these Actiniae were of a light red colour. This colour- 

 ing matter gave two absorption bands in the green which 

 were unfortunately not mapped. 



C(snopsammia. — A Eupsammid coral (Coenopsammia sp.) 

 is extremely abundant about tide mark in sheltered bays at 

 St. Vincent, Cape Verdes, attached to the rock in masses, 

 and very conspicious from its red colour. Some specimens 

 are yelloAV, and some, half red, half yellow, were met with. 

 Also a red specimen with a yellow bud. The red colouring 

 of the corallum gives an absorption band, the position of 

 which Avas not determined. 



ECHINODERMS. 



Purple Pentacrinin. — Many specimens of several species 

 of Pentacrinus were obtained in various parts of the world 

 by H.M.S. Challenger. Several of these species are ncAv, 

 and Avill be described in due course by Professor Sir C. 

 Wyville Thomson, 



Spectroscopic observations Avere made on specimens ob- 

 tained on five different occasions and localities, viz. 



Off the Kermadec Islands, July Uth, 1874, from 630 and 

 650 fathoms. 



Off the Ke Islands, September 26th, 1874, from 126 fathoms. 

 Off Cebu, Philippines, January 26th, 1875, from 100 

 fathoms, Avith Euplectella aspergillum. 



BetAveen Panglaoand Siquijor Islands, Philippines, January 

 25th, 1875, from 375 fathoms. 



Off the Meangis Islands, February 10th, 1875, from 500 

 fathoms. 



The majority of the specimens Avere found to yield a 

 colouring matter Avhich is extremely well defined by char- 

 acteristic absorption s^^ectra, and Avhich may be termed Pen- 

 tacrinin, having as yet, been observed only in the genus 

 Pentacrinus. In the fresh condition the colouring matter is 

 freely soluble in slightly acidified alcohol, and gives a solu- 

 tion which is of an intense pink colour Avhen vicAved by 

 transmitted light. The solution Avhen moderately intense 

 gives a spectrum consisting of three bands (PI. 1, fig. 5 a). 

 One of these, intensely black with sharply defined margins, 

 covers the D line extending for a very short distance 

 beyond the more refrangible side of that line, and for a 

 greater distance on its other side tOAvards the red, as was 



