1898] NOTES AND COMMENTS 151 



species from the island of Billiton, between Singapore and Java. 

 I consider that the distribution of Tunicata as a whole does not 

 lend any support to the bipolar hypothesis. On account of the 

 admitted want of equivalence between the characters made use of in 

 specific and generic diagnosis in the different groups mere lists may 

 be deceptive, especially if drawn up and correlated by one man, who 

 cannot possibly be a specialist on all groups of marine invertebrata. 

 For that reason I now abstain from expressing any opinion except 

 in regard to the group of which I have a more intimate knowledge. 

 It seems to me that this matter must be settled by specialists in 

 each group of animals stating their opinions as to the genetic 

 affinities of the northern and southern faunas in their own groups 

 quite apart from and uninfluenced by general lists containing other 

 groups. The Tunicata instanced by Dr Murray, both in his ' Chal- 

 lenger Summary ' and in his paper on the ' Marine Fauna of the 

 Kerguelen Region/ help to swell lists that assume rather imposing 

 dimensions, but when I examine the case of these species and genera 

 of Tunicata individually, I find that the records of occurrence have 

 to be added to or modified in such a way as to entirely change the 

 nature of their evidence, and show that there is no such close 

 resemblance between the northern and southern polar faunas as 

 Dr Murray and others have supposed." 



Deep Atlantic Holothurlaxs 



Another instance of similarity between N. Atlantic and Pacific 

 forms was recently noted by Mr Eemy Perrier in his description 

 of the deep-sea holothurians, Elasipoda, dredged by the " Travail- 

 leur " and the " Talisman " (Comptes rendus Acad. Set., Paris, exxiii., 

 pp. 900-903, Nov. 1896). He describes Psychrop>otcs buglossa as 

 being a near ally of P. varipes Ludwig, which latter was dredged by 

 the "Albatross" north-west of Cape San Francisco at 1573 fathoms. 

 Unfortunately Mr Perrier does not give either localities or depths of 

 his new species, nor does he figure them ; this is too much to expect 

 in a Preliminary Notice. The chief interest of his paper lies in the 

 rearrangement of the species of Peniagone and Scotoplana according 

 to the nature of the calcareous spicules, and the establishment on 

 the same grounds of a new genus Periamna with triradiate spicules, 

 and having as genotype the Peniagone naresi of Theel. 



BlPOLARITY WITH A VENGEANCE 



We are indebted to Mr Henry Campion of Birmingham for a copy 

 of a 4 8 -page treatise — "The Secret of the Poles" (White & 

 Pike, price Is.). Mr Campion recognises the impossibility of man 

 ever reaching either pole ; at the same time he appreciates the great 

 importance that such an investigation would have, and does his 



