246 THE VOYAGE OF H.M.S. CHALLENGER. 



The colony has been torn from its attachment, which had apparently been among 

 shell debris, or to rock surrounded with the same ; several Balani had bored their way 

 into its base. 



The sterile column is al)out 50 mm. high ; it is broadly but irregularly oval in 

 section, measuring 40 mm. in its broadest, and 27 mm. in its narrowest, diameter. The 

 lower 20 mm. is distinguished from the upper portion by being rough with spicules, 

 whereas the upper part is sraoothish and finely wrinkled and striated. The whole substance 

 is soft and rather spongy in the wet specimen. The capitulum is irregular in form, 

 projecting over the column ; in the wet specimen it is softish. While about 65 mm. in its 

 broadest, its average width is not more than 45 mm. It is deeply plicated ; the plicae 

 form four principal folds, of which the two on the one side are twice as large as those on 

 the other. Each fold is also again deeply notched, one fold even twice. All these folds 

 turn down like the lobes of an ear, and lie against the surface of the column. These 

 lobes are at their bases about 8 mm. in thickness, but decrease to a width of 4 mm. at 

 their free edges, which are somewhat inverted. 



The autozooids are completely retractile within pit-like cavities, the walls of which, 

 on the retraction of the polyps, almost completely close together, leaving but minute 

 dimples to mark their places. The autozooids were in the unique specimen, well filled 

 with ova of varying sizes up to 1 mm. in diameter. They are scattered over the whole 

 of the upper surface of the ca2)itulum, though most crowded at its edges. 



The siphonozooids are numerous, apparently occupying all the spaces not otherwise 

 filled by the autozooids ; about three of them occur in the length of a millimetre. The 

 mesoderm is greatly developed and of a firm gelatinous nature. 



The colour of the whole mass is that of a dull brown. 



The spicules of the sterile stem measure in the trunk : — The curved and straight 

 intercalated spindles 1-0-12; M-O-IG; 0-96-0-14 ; 0-9-0-16 ; 0-56-0-08 mm. The 

 branching spindles measure l"4-0'2 mm. The spiny clubs measure 0'52-0"08 ; 0'4-0'06 ; 

 0'36-0'06 mm. In the capitulum, the ccenenchyma contains some spiny spindles with 

 one end narrow, the other broad, measuring 0-3-0'04 ; 0-3-0-02; 022-0'02 mm. The 

 four-rayed forms measure 0"1-0'1 ; 0'3-0'06 mm. In the tentacles some curved and 

 straight spiny spindles occur, measuring 0'54-0"04 ; 0'44-0'02 mm. 



Ilahitat. — Station 135, Tristan da Cunha ; depth, 60 fathoms. 



This seems to be near Sarcophytum glaucum, but is the only species of the genus 

 from the Atlantic. 



Sarcophytum philippinensis, n. sp. (PI. XXXVIII. fig. 1 ; PI. XLI. fig. 9). 



The colony consists of a sterile stem and an expanded flattened polj^p-bearing capi- 

 tulum. Polyps dimorphic. The mass is attached to portions of broken shells, sand, &c. 



