178 PROCEEDINGS OF THE ROYAL SOCIETY OP QUEENSLAND. 



and measurements made in a liquid medium before 

 staining. 



Measurements are given without the fins. 



1. — Plymouth to Morocco ; 2. — Madeira to the Canary 

 Islands; 3. — West Coast of Africa 15° N. latitude; 4. — 

 West Coast of Africa 1° N. latitude to 1° S. latitude; 

 5. — Durban to St. Paul's Rocks; 6. — St. Paul's Rocks to- 

 122° E. longitude ; 7.— Adelaide to Bass Straits. 



KEY TO THE SPECIES OF SAGITTA. 



The following kej^ to the species of Sagitta has as far 

 as possible been based on those characters which are least 

 likely to be rendered unreliable through damage during 

 capture and subsequent treatment. In species where 

 various authorities do not agree as to the presence or- 

 absence of any particular feature, the species is entered, 

 twice in the key, so that whichever case is correct the species 

 may be identified. 



Collarette present . . . . . . . . . . 1.3 



Collarette absent . . . . . . . . . . 1 



1. Head very large . . . . . . . . . . macrocephala 



Head normal . . . . . . . . . . 2 



2. Tip of seizing jaw hooked . . . . . . 3 



Tip of seizing jaw not hooked . . . . . . 4 



3. Shaft of seisiing jaw serrated . . . . . . serratodentata 



Shaft of seizing jaw not serrated . . . . mini?na 



4. Neck constriction conspicuous . . . . . . 5 



Neck constriction not conspicuous .. ..10 



