686 REPORT— 1894. 



Myotomes 37, 17, 10. 



Snout fin long. 



Caudal fin wide and short. 



IV. Sratichiostoma Cartbaum (Sundevall). 



Distribution. — East Coast of S. America, Gulf of Mexico, West Indies. 



Gonads 27 pairs. 



Both metapleural folds die out behind the atriopore. 



Myotomes 37, 15, 8. 



Snout and tail fins small. 



Anus far back. 



V. Heteropleuron Bassanum. 

 Branchiostoma Bassanum (Giinther). 



Distribution. — Bass Straits, Australia. 



Gonads 30, unpaired. 



liight metapleurou continuous with the caudal fin. 



Ijeft metapleurou dies away behind the atriopore. 



Myotomes 44, 15, 17. 



Snout fin large and pointed. 



Tan fin long. 



YI. Heteropleuron Cultellum. 



Branchiostoma Cidtellum (Willey). 

 Epigonichthys Cultellus (Peters). 



Distribution. — Torres Straits, Australia. 



Gonads 19, impaired. 



Right metapleurou continuous with the caudal fin. 



Left metapleurou dies away behind the atriopore. 



]Myotomes32, 10, 10. 



Dorsal tin very high. 



Anterior expansion of notochord club-shaped. 



VII. Heteropleitrtin Singalense. 



Distribution. — Ceylon. 



< lonads 25, unpaired. 



Right metapleurou continuous with the caudal fin. 



licft metapleurou dies away behind the atriopore. 



Myotomes 39, 17, 8. 



Anus far back. 



Snout and caudal fins small. 



VIII. Assymetron Lucayanum (Andrews). 



Distribution. — Bahamas. 



Both metapleura meet at the anterior end of the pre-oral chamber, and are 

 continuous with the snout fin. 



Oral hood far back, and with few cim, of which two sets, about a median 

 cirrus, are webbed. 



Gonads 29, unpaired. 



Right metajileuron continuous with the caudal fin. 



J.cit metapleuion dies away behind the atriopore. 



Myotonies 44, 9, 1.3. 



Long caudal extension. 



