142 Rev. T. Hincks's Contributions toivards a 



Farciminariadaj, which form anything but a natural group. 

 Indeed, in a natural system such a group could find no place. 

 The cliaracters on which the family is founded are merely 

 zoarial, and tlie chief point relied upon as a diagnostic is the 

 disposition of the zooecia round an imaginary axis, so as to 

 form cylindrical branches. Such a family diagnosis would 

 include a miscellaneous and artificial group between whose 

 members there might be little, if any, natural affinity. Verru- 

 cularia dichotoma^ v. Suhr, would be an alien amongst the 

 forms which compose the family Fai-ciminariadfe of Busk. 



MacGillivray has noticed the " close affinity " in structure 

 between Fhistrella and the present form *, and remarks that 

 " it undoubtedly forms a close connecting-link between the 

 two suborders " (Cheilostomata and Ctenostomata) ; but, 

 " notwithstanding the absence of avicularia and ocecia and 

 the structure of the mouth," he would refer Verrucularia 

 dichotoma to the sameCheilostomatous family as Farcimmaria. 

 ^o reasons are given in support of this decision, but there is 

 much to be said against it. 



The mode in which the zooecia are disposed and the habit 

 of tiie zoarium, it is now generally admitted, are not characters 

 which can be relied upon as indications of natural affinity. 

 Agreement in these points is commonly associated with the 

 most significant structural differences. In the present case 

 the two forms in question are distinguished by very different 

 types of orifice and oral operculum. In Farciminarla the 

 orifice presents the normal Cheilostomatous character ; in 

 Verrucularia dichotoma it is distinctly bilabiate, bounded 

 above and below by a chitinous rib, the lower one (probably) 

 connected with a movable lip. This is an important differ- 

 ence, which forbids the union of the two forms in the same 

 family group. 



The present condition of my specimens of Verrucularia 

 prevents me from completing my study of the structure ; but 

 enough has been determined to prove that it must be separated 

 from Farciminaria. Provisionally, at least, it may be asso- 

 ciated with Flusfrella, with which it seems to be most closely 

 connected. 



Ibid. (p. 368). 

 Cellaria Jistulosa, var. australis, MacGillivray. 



There is no doubt that this form should be accounted a 

 distinct species, as I have suggested f. 



* ' ZoologT of V'ictoria,' vol. ii. p. 348. 



+ See Waters, ' Challenger ' Rep. p. 16, pi. ii. figs. 1-4. 



