302 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



other characters as in A. bas- 

 sanum. 

 (ii.) Ventral fin has fin chambers but no 

 fin rays- 



A. cultellum — Length 35 mm.; 

 myot. 50-56 ; formula 32, 10, 10 ; 

 dorsal fin swollen anteriorly ; 

 notochord club-shaped at anterior 

 end ; oral sphincter over 6th 

 myotome; 41-43 oral cirri. 

 (B) Species witJi a long urostyloid process 

 into which the notochord is prolonged ; 

 oral cirri have no sense papillae; post- 

 atrioporal caecum paired; ventral fin 

 with neither fin rays or fin chambers. 

 A. lucayanum — Length 10-30 mm ; 

 myot. 63-66 ; average formula 

 44, 9, 13 ; oral sphincter over 

 myot. 8 ; 10 intra-buccal ten- 

 tacles; 21-29 pre-oral cirri; 26- 

 29 gonads; no nephridia accor- 

 ding to F. Cooper. 

 A. caudatum— Length 20 mm.; 

 myot. 60-64 ; formula 44, 9, 11 ; 

 rostral fin and caudal process 

 separated from the rest of the 

 body by a constriction. Other 

 characters as in A. lucayanum. 



