114 J- B - JOHNSTON. 



(p. 16) : "Si Ton examine tres attentivement des diverses parties 

 constituantes, aux differents stades de leur developpment, de cette 

 double ebauche radiculaire, nulle parte on ne constate une trace 

 d'ebauche ganglionaire. L'etude de 1'Amphioxus adulte, a 1'aide 

 de la methode de Golgi, a 1'aide du bleu de methylene et a 1'aide 

 des methodes ordinaires, ne revele 1'existence d'aucune cellule 

 ganglionnaire proprement dite sur le trajet des racines dorsales, 

 mais devoile leur presence a 1'interieur du nevraxe lui-merne. 

 Nous croyons done pouvoir en conclure qu'il n'existe point de 

 ganglions spinaux ni de ganglions craniens sur le parcours des 

 racines dorsales chez 1'Amphioxus." 



Dogiel (5) has described at length certain structures which he 

 finds attached to the nerve rami just distally from the point of 

 division of the dorsal roots into dorsal and ventral rami. The 

 structures appeared in animals subjected for a long time to methyl- 

 ene blue in physiological salt solution. They were never stained 

 by methylene blue dissolved in sea water. Dogiel was uncertain 

 whether they may not have been artificial products due to im- 

 mersing the animals in physiological salt solution. He was 

 unable to make out their structure in preparations fixed and 

 stained in various ways. He decided that they are normal 

 structures, however, since they stain well with gold chloride and 

 are visible in animals treated with osmic acid. The structures in 

 question are rounded or pear-shaped bodies which are found in 

 clusters of two, three or four attached to the nerve rami as berries 

 are attached by their stems. The author concludes : " Samtliche 

 aufgezahlten Thatsachen lassen sich am ehesten in der Weise 

 auslegen, dass die beschriebenen Elemente Analoga von Spinal- 

 ganglien darstellen, welche beim Amphioxus moglicherweise in 

 einer embryonalen Entwicklungsform vorhanden sind. Eine 

 endgiltige Entscheidung der Frage iiber die Natur dieser Gebilde 

 ist jedoch naturlich nur dann moglich, wenn die Structur dersel- 

 ben und ihre Beziehung zu den Nerven sicherer bestimmt sein 

 wird." 



I can add with regard to these structures, first that they do 

 stain by methylene blue dissolved in sea-water, and second that 

 they are to be found along the course of the ventral ramus as 

 far ventrally as the middle of the lateral surface of the body. 



