Xiv. 
ORDER PROSOBRANCHIATA. 
SUB-ORDER PECTINIBRANCHIATA. 
A. 'TOXOGLOSSA. 
Conida. 
Our British Pleurotomoid forms require careful grouping. Mangilia, 
Risso, has as type WM. costulata, Risso, which, according to Jeffreys, 
= nebula, Mont.; again Bela (Leach), Gray, has as type, nebula, 
Mont., while Raphitoma, Bellardi, belongs to the same group. Further, 
Defrancia, Millet, is preoccupied by Brown in Bryozoa, therefore dealing 
conservatively—in the present state of uncertainty—we propose that 
Mangilia should stand for the group ot nebula, &c., with Hedropleura, 
Monterosata, as a sub-genus for septangularis, and Thesbia, Jeff., as 
another for M. nana, Lovén; while Clathurella, Carpenter, shouid cover 
the forms allied to purpurea, with Teretia as a subgenus for teres, 
Forbes. According to 1ecent authors Donovania, Bueq., Dautz, and 
Dollf. = Lachesis, Risso, non. Daudin, nec Savigny, should be placed 
here rather than with the Muricide. The type is D. minima, Mont. 
B. RACHIGLOSSA. 
Fasciolariide, 
The following forms have appeared in most British lists as ‘‘ Fusus” : 
They do not however accord with the typical forms of that genus, and 
may be divided as follows :— 
Neptunea, Bolten, 1798. 
N., antiqua, L. 
Tritonofusns, Beck, 1847, 
(type) T. islandicus, Chemn, 
T. gracilis, Da Costa. 
T. propinquus, Alder. 
T. Jeffreysianus, Fischer. 
T. fenestratus, Turton, 
Troschelia, Aférch, 1876. 
T. Berniciensis, King. 
