349 



Nachdruck verboten. 



The „Cirrhostomial" Origin of the Head in Vertebrates . 



Preliminary notice by H. B. Pollaed, 



Owens Coll. Manchester. 



With 4 figures. 



Examination of the third tentacle of Myxine reveals the follow- 

 ing characteristics. The free portion or cirrus contains a core of a 

 tissue which may be termed precartilage (Parker) since it is that 

 tissue which both in ontogeny and phylogeny precedes hyaline cartilage. 

 It is a dense tissue with an intercellular matrix. The cirrus passes 

 continuously into a rootpiece the histological condition of which is 

 peculiarly modified in Cyclostomi. 



In the rootpice the nuclei and protoplasm of the procartilage 

 cells have disappeared leaving only a hard yellow spongework of the 

 intercellular matrix. From the basal portion of the rootpiece connec- 

 ting bars of procartilage pass to corresponding other rootpieces. 



To the cirrus and rootpiece of the third tentacle are attached 

 certain muscles which mostly are inserted on the cirri and rootpieces 

 of other tentacles. 



In the case of the third tentacle the muscles are 



1) Zurückzieher der Tentakeln (J. Müller *) = Tentacularis 

 posterior (P. Fürbringer 2 ); 



2) Compressor des Mundes (M.) = Tentaculo-ethmoidalis (F.); 



3) Zurückzieher des Mundrandes oder der Mundknorpeln (M.) = 

 Palatocoronarius (F.); 



4) Zweiköpfiger Herabzieher des Mundes (Kopf U' M.) = Copulo- 

 tentaculo-coronarius (F.); 



5) A small muscle. 



According to P. Fürbringer 3) and 4) are supplied by the Kamus 

 externus Maxillaris, 1) by a spinal nerve and 2) by the Ophthal- 

 micus (0. profundus). I cannot agree with all Fürbringer's determi- 

 nations. Thus by tracing the nerve supply in sections I find that 1) 



1) Johannes Mülleb, Vergl. Anat. der Myxinoiden, Berlin 1835. 



2) Path, Fübbbingee, Unters, z. vergl. Anat. d. Musk. d. Kopfskelets 

 der Cyclostomen, Jenaische Zeitschrift, Bd. IX. 



