THE SYSTEM OF FI1YLLOFIIORIN/E. 



63 



vom linken dorsalen Radialkanal und endlich der Fühler des rechten 

 dorsalen Interradius vom rechten dorsalen Radialkanal versorgt 

 werden." Der sechste und siebente" continues the author, 



,, iiegen in Bezug auf die Medianebene der Holothurie einander genau 

 gegenüber und erhalten ihre Wasserkanäle von denjenigen beiden 

 Radialkanälen, welche sich bisdahin an der Abgabe von Fühlerkanälen 

 überhaupt noch nicht betheiligt hatten, nämlich von dem linken 

 ventralen und dem rechten ventralen." . . . . „.Beide Radialkanäle 

 entsenden den neuen Fühlerkanal in dorsaler Richtung, also in den 

 linken, bez. rechten dorsalen Interradius." The pairs of primary 

 tentacles, given off from the left dorsal and the midventral radial 

 canal, are each made up of exactly opposite and equal-sized 

 tentacles ; therefore it Can not be determined whether these appeared 

 simultaneously or not, and if the latter be the case, which appeared 

 first. At any rate, from the fact that the right dorsal radial canal 

 gives off the first tentacular canal ventrally, it may be inferred • that 

 the order of appearance of tentacular canals does not correspond with 

 their manner of branching in the adult. 



Of great interest is Edwards' observation [12, pp. 216— 220] on 

 HolotJmria floridana that, in each radius, the tentacle which corres- 

 ponds to the first in polychirotous forms invariably, appears first, 

 while that corresponding to the fourth appears last. Moreover, the 

 order of appearance of the four tentacular canals from the midventral 

 radial canal is exactly in agreement with the branching order seen 

 in Pscudocucumis africamts. 



5. Systematic value of tentaculation in 

 the Caciiinariidœ. 



The characters made use of for distinguishing genera and species 



* Strangely enough a quite contradictory statement was made by the same author at 

 another place, to the effect that the right dorsal radial canal gives off a tentacular canal 

 „ nur an seiner dorsalen Seite " [27, p. 608]. 



