98 W. BLAXLAND BENHAM. 



bars, but in Amphioxus as a whole, coelomic spaces from 

 blood-vessels. It is chiefly with regard to the interpretation 

 of the spaces within the tongue bars that Spengel joins issue 

 with him, and it was to this part of the subject that I directed 

 ray attention last summer in the endeavour more especially to 

 decide whether the cavity traversing the ^'chitinoid^^ rod of the 

 tongue bar be ccelora (Lankester) or blood-vessel (Spengel). 



I hoped to decide the question by the examination of speci- 

 mens which had been fed with carmine ; and for this purpose 

 Professor Lankester requested Mr. A. Willey, who was then at 

 Naples, to feed some animals and preserve them for me. My 

 thanks are due to Mr. Willey for so doing. Unfortunately, 

 however, these carmine-fed specimens have not been of much 

 value for my purpose, and I was compelled to fall back upon 

 carefully preserved specimens (in picro-sulphuric acid) stained 

 in various media. This was the method followed both by 

 Lankester and by Spengel — careful tracing of spaces from 

 section to section in order to ascertain their communication 

 with other cavities about whose nature there is no doubt. 



Before I had completed my work, Boveri's most interesting 

 paper on the nephridia was published. Boveri found, as I had, 

 that Spengel, both in incomplete observation and in certain 

 interpretations, had fallen into errors similar to those which 

 with an accompaniment of gratuitous insolence he had attri- 

 buted to Lankester. 



This short note may conveniently be divided as follows : 



A. Description of the tongue bar, according to my own ob- 

 servations, and comparison of it with the primary bar. 



B. Interpretations of the parts of the tongue bar. 

 c. The observations of recent observers. 



D. Certain abnormalities in the pharyngeal bars. 



The authors who have described and figul'ed the gill bars of 

 Amphioxus, to whom I shall have occasion to refer, are — 



1. Stieda. — " Studien iib. d. Amphioxus lanceolatus," 'Mem. Ac. Sci. 

 Petersbourg,' xix, 1873. 



