244 MK. J. W. GKEGOET ON THE 



It may be objected that the genera of the Adeonince are based on zoarial 

 characters ; but these are of such a marked description, and lead to such modifications 

 and dimorphism of some of the zocecia, that they seem certainly of generic value. In 

 regard to Adeona and Adeonellopsis there is the further difference of the presence of a 

 peristomial pore in the latter. 



It seems also advisable to rediagnose Adeonella in accordance with this scheme, and 

 consider what species should be included in it. But at present the diagnosis of the 

 genus is the same as that of the family, as I am at present aware of only the one genus; 

 the diagnosis is therefore : " Schizothyriata with a schizostomatous primary aperture 

 and a secondary orifice variable in form. Gonoecia present, but no externarmarsupia." 

 Before giving a list of the species I had better refer to the question of the value of the 

 peristomial pore, as if Busk [No. 8, p. 167] and Eidley [No. i, p. 47, pi. vi. fig. 6] are 

 right in considering it of generic importance, then Adeonella must be subdivided. Since 

 Mr. Kirkpatrick [No. i, pp. 77, 78, pi. viii. fig. 5] has shown that this structure in 

 " Gigcmtopora " lyncoides, Ridley [No. i, p. 47, pi. vi. fig. 6], is only formed by the 

 avicularia, little value has been attached to it. Messrs. Hincks [No. 6, pp. 268, 269J 

 and Waters [No, g, p. 192] also dismiss it as valueless, as the bridge is not always 

 present in different zocecia of the same zoarium of Schizoporella Uturrita, Hincks (or 

 S. tuherosa, Eeuss). 



List of Species of Adeonella. 



Type. Adeonella polymorpha, Busk, No. 8, p. 183, pi. 



Adeonella, dr. polymorpha, Gioli, No. i, pp. 261, 362, pi. xiv. fig. 8. 



platalea, Busk, No. 8, p. 184. 



intricaria, Busk, No. 8, p. 185. 



regularis, Busk, No. 8, p. 186. 



atlantica. Busk, No. 8, p. 186. 



pectinat.a. Busk, No. 8, p. 189. 



(This species has a large lyrula withiu the secondary orifice and hiding the primary aperture. 



Busk has not figured the operculum, but its shape shows that the primary aperture is 



schizostomatous. It ought, perhaps, to be sepai-ated as a subgenus.) 



polystomella (Reuss), No. i, p. 70, pi. viii. figs. 37, 38. 



pallasi (Heller), No. i, p. 115, pi. iii. figs. 1, 2? = A. polystomella. 



dispa?- (Macgill.). For references see Jelly, No. i, p. 259 (agrees with Adeonella, but has a 



sinus also in the secondary orifice). 

 — sulcata (M.-Edw.), Eschara sulcata, M. -Edwards, No. i, pp. ■47-4<9, pi. v. fig. 2, non 



Flustra sulcata, Lamouroux, No. 3, p. 609, pi. 92. figs. 3, 4. 

 ■ fuegensis (Busk), No. 3, p. 90. 



