834 Proceedings of the Royal Irish Academy. 



raeter of ^oUdiella glauca which appears to distinguish it from 

 the closely related vS". Alderi, and from Eolis angulata. This 

 point has been apparently overlooked by Vayssiere, who unites 

 the two latter species with ^. glauca. Unfortunately Alder 

 and Hancock give no information respecting the radula of 

 E. angulata, but the fact that they place the species in the 

 sub-genus Cavolina in close company with such species as 

 C. concinna and C. oUvacea shows that they did not regard it 

 as closely related to ^. glauca. 



The radula of Plymouth and Yalencia specimens agrees in 

 character with vE. glauca. 



Sub-family — Ceatenid^. 

 It appears to me that, in some cases at least, Bergh's very 

 minute sub-division of the Solids is unsatisfactory. In 

 particular the sub-families Cratenidse and Tergipedinse are 

 insufficiently characterised (not to say erroneously). Take, for 

 example, the genus Ampliorina (Tergipedinse) : apart from some 

 slight and not easily seized difference in the shape of the papil- 

 lae, Amphorina approaches in external features and radula very 

 closely to Cratena. According to Bergh's diagnoses, however,, 

 Ampliorina has an armed penis and a single otolith in each 

 otocyst, while Cratena has its penis unarmed and otocysts con- 

 taining otoconia. But in point of fact all the Cratenae which I 

 have had an opportunity of examining ( C. amcena, 0. olivacea, 

 and C. viridis) have a single otolith in each otocyst, and, with 

 the possible exception of the last-named, have an armed penis, 

 essentially like that oi Amphorina- Cavolina ( Cuthona) aurantiaca, 

 placed by Bergh provisionally among the Cratenidae, also has a 

 penis of similar character. Obviously either a revision of the 

 characters of sub-families and genera is necessary or a re-assort- 

 ment of species. Under these circumstances I have pro- 

 visionally revived the genus Cavolina as used by Alder and 

 Hancock.^ 



Genus — Cuthona. 

 Cuthona Peachii, A. & H. 



JEolis ( Cuthona) Peachii, A. & H. 



A single specimen, which I refer to this little-known species, 

 was dredged in Yalencia Harbour in May, 1895, on the Pecten 



' Cratena paradoxa, Nichols (fide Gamble), Proc. Roy. Irish Acad., ser. 3^ 

 vol. v., 1900, p. 587, = Acol. glauca, juv. 



