356 ESCHARID^. 



tation of the present species ; but it is so entirely wanting 

 in character, and fails so completely to give the striking 

 features of S. trispinosa, that it is practically useless for 

 the purpose of identification ; and as it is unaccompanied 

 by a diagnosis, I am unable to see that it gives any claim to 

 the name with which it is associated. 



Genus PHYLACTELLA, Hincks. 



Der. From ^tAaicrie, fortified. 



LEPRALIA (part.), auctt. 

 ALYSIDOTA (sp.), Busk. 



GENERIC CHARACTER. ZOCECIA with the primary orifice 

 more or less semicircular, the lower margin usually den- 

 tate; peristome much elevated, not produced or channelled in 

 front. No AVICULARIA. ZOARIUM (in British species) 

 incrustina. 



THIS genus is instituted for two or three species which 

 seem to lie outside the preceding, though nearly related to 

 it. P. labrosa, with its triplet of denticles, its elevated 

 peristome, and its porous surface, exhibits much affinity 

 with such forms as S. Landsborovii. P. eximia agrees 

 with it in most points; but the pores are only present 

 round the margin. In P. collaris both pores and denticles 

 have disappeared. The chief distinction between this 

 genus and the last lies in the character of its raised peri- 

 stome, which in Smittia contracts in front into a chan- 

 nelled sinus, whilst in Phylactella it is entire. The pri- 

 mary orifice in the latter is almost semicircular. 



