156 Rev. T. Hincks's Critical Notes 



MacGillivray adopts the family Adeonidse, as constituted bj 

 Busk, but adds nothing to the evidence in its behalf which I 

 have just discussed *. He proposes the generic name Adeonel- 

 lopsis for the section of Busk's Adeonella characterized bj the 

 presence of true pores, and assigns the species with a peri- 

 stomial opening to the Adeonella of Waters. The latter, 

 however, as I have already remarked, has not been strictly 

 defined, and as at present understood includes in all proba- 

 bility very dissimilar forms. Of the ' Challenger ' species 

 referred to it [Waters, loc. cit.'\ A. i)olymorpha and A. atlan- 

 tica must be accounted doubtful. I should certainly hesitate 

 to place them at all w^ithout the opportunity of examining 

 specimens. In the case of the latter the description is incom- 

 plete. A. platalea seems to be distinctly related to the 

 lSchizoporellida3 ; the primary orifice is represented as deeply 

 sinuated. The large spoon-shaped avicularium is a character 

 which it shares with S. spongites^ Smitt. The peristomial 

 opening is not a distinctive feature. A.intricaria has a peri- 

 stomial opening and an orifice with a straight lower margin, 

 gonoecia, and avicularian cells. It is one of the forms 

 which apparently must be separated from the Microporellidai, 

 A. pectinata must be placed amongst the doubtful forms. We 

 have no account, as it seems, of iXxQ primary zooecial orifice; 

 the " mouth," described as having " the lower lip " straight, 

 appears to be the secondary orifice ; nor is it easy to under- 

 stand " the reniform " pore placed low down on the " ooecial 

 cells." The zooecial pore is described as " sublabial," and 

 must be a peristomial opening. The remaining species 

 assigned by Waters to his genus Adeonella is Schizoporella 

 jpolystomella^ Reuss {—S. Fallasii^ Heller), of wliich I have 

 already spoken. There is clearly room for much further in- 

 vestigation of the forms referred to the genus Adeonella, Busk, 

 in the 'Challenger'' Report. A. distoma seems to be the 

 only true Microporellidan included in it, so far as we are able 

 to judge. 



A question remains : Is there any sufficient ground for 

 dividing the genus Adeona ? Busk has shown f that the 

 flexible stem is really the only character to which much 

 importance can be attached that separates this form from 

 Adeonella. The mere habit of growth would not count for 

 much even if it were constant ; but from Kirchenpauer's 

 figures J it appears that there are two species furnished with 



* " Descriptions of new or little-known Polyzoa. — Part IX.," Trans. 

 Royal Soc. Victoria, 1886. 



t ' Challenger ' Report, p. 183. 



t " Ueber die Bryozoen-Gattung Adeonio,'' 1879, plate i. figs. 2, 8. 



