304 J. W. KIRKALDY. 



5. Four specimens from Ceylon collected by Mr. Haly, 

 and lent to Professor Lankester by Professor Haddon (H. 

 cingalense). 



6. Eight specimens from the coast of Brazil, presented to 

 Professor Lankester by Professor van Beneden of Liege 

 (A. caribseus), by whom they were collected. 



7. Twelve specimens from the Bahamas presented to Pro- 

 fessor Lankester by Professor Alexander Agassiz^ by whom 

 they were collected (A. Lucayanum). 



8. Five specimens from Ceylon, forwarded to Professor 

 Lankester by Professor Good Brown, of the National Museum, 

 Washington, U.S.A. (H. cingalense). 



9. Ten specimens from the coast of California forwarded to 

 Professor Lankester by Professor Good Brown. Cooper's type- 

 specimen of A. californiensis was among these. 



10. In addition to the above-mentioned material which I 

 have been able to study, and in many cases to examine, by 

 means of transverse sections in Professor Lankester's labora- 

 tory at Oxford, I have been allowed by Dr. Giinther to examine 

 the specimens of another species (A. Belcheri), of which 

 only five exist, in the British Museum. 



I am desired by Professor Lankester to express his great 

 obligations to Professors Spencer, Haddon, van Beneden, 

 Agassiz, and Good Brown for their kindness in communicating 

 their specimens to him. 



For the nomenclature of the various structures of the 

 Branchiostomidse already in use the reader is referred to Pro- 

 fessor Lankester's memoir (No. 7), and to the recently pub- 

 lished work by Dr. Arthur Willey (No. 15). 



The characters to which I have, at Professor Lankester's 

 request, given attention, and have found to be important for 

 the purpose of dividing the Branchiostomidse into genera, sub- 

 genera, and species, are as follows. I enumerate the characters 

 approximately in the order of importance which it has been 

 found necessary to assign to them. 



1. Prgeoral cirrhi uniformly connected to one another by a 

 low web, or per contra separated into two ventrad and two 



