1898.] PLANJtTOiS^ OF THE PAEROE CHANNEL. 1025 



also a few which may be radiate, or may be only broken off from 

 the end of a geminate-radiate spicule. 



The horizon of capture was doubtful ; one specimen was taken 

 at 13 e, one at 13 ah. 



SiPHONOsPHiEEA (Holosiphonia) tizardi, sp. n.^ (Plate LXVI. 

 fig. 1.) 



Definition of the Species. — Colony spherical (? always), up to 

 about 2 mm. diameter. Zooids with a single spherical lattice-shell 

 about -15 mm. in diameter, which is beset all over by short broad 

 tubes. The tubes are very thin-walled and fragile, their walls 

 slightly convergent, '010 to '018 mm. in diameter, and about 

 •005 mm. high ; there are five to seven tubes on the half meridian, 

 Endosarc with very numerous nuclei ; oil-globules ? ; zooxanthellae 

 very numerous, both inside and outside the shell, and also scattered 

 through the calymma between the zooids. 



In some hauls large numbers of the zooids had apparently 

 broken away from the calymma, and appeared as solitary organisms 

 referable to the family Liosphserida. As a warning to describers 

 of Liosphserida, I may say that I had actually identified them as 

 Ethmosjjhceni leptosiphonia, described by Haeckel from the Eaeroe 

 Chanuel, before I fovmd them united in a colony. 



So far as the evidence goes, the species is purely epiplanktonic ; 

 as it is a very conspicuous form, and it occurs with fair regularity 

 at the surface (23 7o of epiplankton hauls), and never with 

 certainty in mesoplankton hauls, I think we are justified in 

 accepting the evidence as fairly conclusive. 



For the horizons of capture, see the table on p. 1022. 



Eadiolaria Acantharia. 

 Acanthometron catervatum Haeckel {=A. brevispina Hkl.) was 

 present in most hauls with the fine-meshed net in 1896, often 

 in suflicient quantity to give a red tinge to the contents of the 

 tow-net. In 1897 (Station 20) it was practically absent from the 

 surface, like most things. A similar abundance and scarcity were 

 recorded by the ' Knight Errant ' in 1880 in this district ^ 



Eadiolaria Ph^odaeia. 



This interesting group of Radiolaria was well represented in 

 the ' Research ' collections, but not so well as in the 'Triton' 

 collections made by Sir John Murray in 1882. 



The data afforded by my captures show the extreme danger of 

 drawing conclusions as to the vertical distribution of a species 

 from a few observations at a single " station." I have alreadv 

 pointed out ^ that adequate data for this work can only be obtained 



'^ I have pleasure in associating with this species the name of Captain T. H. 

 Tizard, E.IN., who explored the B^eroe Channel in command of the 'Knight 

 Errant' (1880) and of H.M.S. 'Triton' (1882), to whom 1 am indebted fojr 

 mnuh vii.Uiable help. 



^ T. JS^. Tizard and J, Murray, Proc. Roy. Soc. Edinburgh, xi. p. 654. 



3 Proc. Zool. Soc. 1898, pp. 578-580. 



