292 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



species. It was the geographical distribution which 

 apparently was the greatest argument for its separation 

 from A. lucayanum. It was during the examination of 

 A. caudatum that he made the statement quoted above in 

 discussing B. nakagaivcc, and he evidently then thought 

 that the slight differences between his species and .4. 

 lucayanum became of great importance because these 

 forms were found at far distant points. Dr. Willey 

 evidently had changed his opinion later when, in 1901 ^ 

 he states, " if we regard A. caudatum to be merely of 

 sub-specific rank, as would seem to be the case." More- 

 over, Mr. J. S. Gardiner has since found A. lucayanum 

 round the Maldive Islands in the Indian Ocean, and this 

 at once does away with Dr. Willey 's seeming difficulty 

 in realising that the same species may occur in widely 

 separated parts of the globe. The amended classification 

 would, therefore, in view of the above discussion, be as 

 follows : — 



Order CEPHALOCHOKDA, Lankester, 1877. 

 Family Branchiostomid^e. 



Genus I. Branchiostoma, Costa, 1834. 



(Amphioaus, Yarrell, 1836). 



B. lanceolatum (Pallas, 1774). 

 B. lanceolatum, var. belcheri. 

 B. lanceolatum, var. caribbaum. 



B. elongatum, Sundevall, 1853. 



B. calif orniense, J. G. Cooper, 1868. 



B. pelagicum, Giinther, 1889. 



B. indicum (Willey, 1901). 



B. cajiense, Gilchrist, 1902. 



i Q.J. M.S. Vol. xli. 



