Natural History of East Finmarh. 117 



specially placed all the species of the ventricosa section first, 

 both in his original creation of the genus in 1879 and in his 

 work ; and we have seen that Escharoides can be used for 

 the appensa section, but could not be used for the other. 



Genus Escharella, Gray^ 1818. 

 = MucroneUa, Hincks, 1879. 

 Type, Escharella immersa (Fleming) { = L. Peachii 

 Johnston) . 



Zooecia convex or somewhat flattened ; front wall strongly 

 calcareous and granulated, generally imperforated on all the 

 central portion ; round the base a row of pores. Oral 

 opening semicircular or nearly so, a mucro on the lower lip, 

 and within it a simple or bifid denticle and a " well-developed 

 oral bow^^ [Levinsen] . Operculum membranous. Ooecium 

 semiglobose, imperforated. No avicularia. Rosette-plates 

 very numerous (about 18-21) and carried round the distal 

 margin, of the same character as those of the lateral margins. 

 The passages of communication between the walls of the 

 zooecium in this genus make a pretty appearance ou the back. 

 Levinsen's figure of the back of E, immersa (2ool. Dan. 

 pi. vi. fig. 3) is illustrative of all the species, though each 

 has a character ot its own. As regards the number, I shall 

 count the number of the upper half of a side of the zoceciurn 

 to the centre of the distal margin, and the rosette-plates for 

 a whole side will therefore be double that of the number given : 

 ventricosa, 8-10 ; immersa, 5-7 ; variolosa, 10-12, the wall 

 very thin ; abi/ssicola, about 10. 



Of sjjecies which should be excluded from Escharella — 

 appensa, Hassall { = coccinea auct., but ? Abildgaard). — 

 The back as well as the front of the zooecium is utterly 

 different from that of the true Escharellcp.. It is like that of 

 a Callopora or Lepraiia [ = Membraniporella) , for there are 

 one distal and two lateral pore-chain bers exactly as in those 

 genera. This species should, I think, be regarded as the 

 type of Milne-Edwards's genus Escharoides, Levinsen 

 (" Studies of Bryozoa,^^ p. 26) has created a genus Peristo- 

 mella for it. 



pavonella, Alder, is equally removed as the last from 

 ventricosa ; for the whole side of the zooecium there are only 

 two rosette-plates. Harmer would place it with verrucosa 

 in the genus Umbonula, or, as I should say, Discopora. 



microstoma, Norman. — 1 have not satisfied myself as to 

 the position which this species should take; the semierect 

 mouth, which is very small and round, and tiie ooecium tilted 

 back off the zooecium, seem to point to alliance with such 

 a species as shiccra. 



