346 



garded as supporting the theory of the »lateral notochords«. I have 

 already shown that I cannot admit any relation between these parts 

 of the pharynx and the »Eicheldarm« oî Balmioglossus^ and without 

 establishing that homology, I do not see that Mr. Master man has 

 much reason for regarding them as notochords at all. 



The morphology of the » lateral notochords « of Actinotrocha is a 

 more difficult question. It seems to me that Mr. Masterman has 

 hardly sufficient evidence to justify him in concluding that the pig- 

 mented appearance of these organs described by earlier observers, and 

 supposed to indicate hepatic functions, was due to the presence of 

 minute vesicles in which the dark appearance is »formed in the same 

 way as the black rim of an air-bubble under the microscope (f. If, how- 

 ever, the »lateral notochords« are really represented in Cephalodiscus 

 and Balanoglossus^ they might either be regarded as rudimentary gill- 

 slits (a possibility considered, but rejected, by Mr. Masterman) or 

 they might correspond with the dorsal branchial part of the pharynx 

 in those forms. 



The transition from these »notochords« to the arrangement found 

 in the higher Chordata is believed to be afibrded by Balanoglossus. If 

 I have shown that Cephalodiscus afi'ords no support to the theory of the 

 originally paired character of the notochord of Balanoglossus^ an im- 

 portant part of Mr. Masterman' s arguments is removed. Under these 

 circumstances it appears to me that the name Diplochorda, proposed 

 by him for the reception of Phoronis, Cephalodiscus and Rhahdopleura, 

 is a misleading one, which should not be allowed a permanent place 

 in Zoological literature. 



Kings College, Cambridge, August 25, 1897. 



4. Über einige myrmecophile Acarinen. 



Von E. Wasmann S. J. (Exaeten b. Roermond). 

 Zweite Mittheilungi. 



eingeg. 29. August 1897. 



Über Hypopen in Ameisennestern. 



Durch die Freundlichkeit von Herrn A. D. Michael (London) 

 war es mir möglich, über die Hypopen in meinen Beobachtungsnestern 

 etwas mehr Klarheit zu erhalten, worüber hier ein kurzer Bericht ge- 

 geben werden soll. 



Bezüglich der Acarinen in dem großen Beobachtungsnest von 



1 Vgl. Zool. Anz. No. 531. 



