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



in fig. 23 {Thccophora semisuberites) of the Depths of the Sea; when, on the other 

 hand, the animal is contracted, the top of the sponge, owing to the arrangement of the 

 brushes of spicules immediately below the surface, becomes uneven and " scaly " 

 in appearance as in fig. 24 {Thecophora ihla) of the Depths of the Sea. Evidently, 

 when living, the sponge possesses great power of contractility, a power which would appear 

 to be shared in large measure by the oscular tube. 



Vosmaer, in his Report on the Sponges of the " Willem Barents " Expedition of 

 1880 and 1881 (p. 18), has given some account of the minute anatomy of this 

 species, and some observations on this subject are also given in the Introduction to 

 the present work. 



Zoca/iii'es.— Station 49, May 20, 1873; lat. 43° 3' N., long. 63° 39' W.; south of 

 Nova Scotia; depth, 85 fixthoms ; bottom, gravel, stones; bottom temperature, 35°'0. 

 Ten specimens. 



Station 50, May 21, 1873; lat. 42° 8' N., long. 63° 39' W.; south of Nova 

 Scotia; depth, 1250 fathoms; bottom, blue mud; bottom temperature, 38°'0. One 

 specimen. 



Inaccessible Island, October 16, 1873 ; depth, 60 to 90 fathoms. Four small 

 specimens of a dwarf variety. 



Habitat. — Arctic Seas (Schmidt, Vosmaer, &c.) ; North Atlantic (Carter, &c.) ; Gulf 

 of St. Lawrence (Whiteaves) ; Newfoundland (Smith and Harger) ; off Nova Scotia 

 (Challenger) ; Inaccessible Island (Challenger). 



Genus Stylocordyla, Wyville Thomson (PI. XLIIL). 



1869. Hyalonema (pars), Lov^n, Ofversigt k. Vetensk.-Akad. Fiirhandl., vol. xxv. p. 119. 



1873. Stylocordyla, Wyville Thomson, The Depths of the Sea, p. 113. 



1876. Polymastia (pars), Carter, Ann. and Mag. Nat. Hist., ser. 4, vol. xviii. p. 393. 



1880. Stylorhiza, Schmidt, Spong. Meerb. von Mexico, pt. ii. p. 79 ; pi. x. fig. 5. 



1881. (?) Rldzaxinella, Keller, Arch. Micr. Anat., vol. xviii. p. 271. 



Sponge corticate, differentiated into distinct head and stalk. Skeleton in head radiately 

 arranged, with a cortical layer of smaller spicules set vertically to the surface ; skeleton 

 in stalk consisting chiefly of a dense axis of longitudinally arranged spicules. Spicules 

 oxeote only. 



This genus still stands aloof from all other Suberitidse in its remarkable spiculatiou, 

 though, as regards external form, the old distinction embodied in the term Stylocordyla 

 no longer holds good, for similar stipitate forms are found to occur in the genus Suherites 

 {e.g., Suherites ramulosus, nobis). 



Only one species of the genus is as yet established satisfactorily (see sjmonyms and 

 references below). 



