35 



Calcareous Sponges. Fifty recent genera are recognised and 

 diagnosed, and all the described species, amounting to 433, are 

 arranged under theise genera. The rejected generic names, which 

 are listed separately, amount to 97. The fifty accepted genera 

 are grouped in 10 families, and Polejaeff's subdivision into 

 HomoccEla and Heteroccela is abandoned. The systematic part 

 of the work is prefaced by a discussion on the principles of 

 classification, and followed by a discussion on the phylogeny of 

 the group, accompanied by a genealogical tree. The suggestions 

 of Minchin and Bidder as to the systematic value of the position 

 of the nucleus of the collared cell is followed up, and this position 

 has been determined in 75 species. It appears from the evidence 

 thus secured, taken, of course, in connection with other characters, 

 that in the primitive family Plomoccelidse the position of the 

 nucleus is basal in some species and apical in others, but that it 

 is not correlated with other characters so as to justify a sub- 

 division of the family accordingly. From the Homocoelid^e, 

 however, two lines of descent have sprung, the one basinucleate 

 and the other a.picinucleate ; the former including the families 

 Leucascidfej Leucaltidse, Minchinellidte and Murrayonidfe, and 

 the latter the Sycettidse, Heteropiidse, Grantiidas, Amphoriscidse 

 and Lelapiidte. 



Surgeon J. C. Thompson, U.S.JST,, sent a paper, communicated 

 by Dr. F. E. Beddard, M.A., F.R.S., F.Z.S., containing con- 

 tributions to the Anatomy of the Ophidia. 



The Secretary communicated a paper by Prof. T. "Wingate 

 Todd, M.B., F.R.C.S., entitled " Observations on Osteomalacia in 

 the Zoological Collections of Manchester and Cleveland," 



This Meeting closes the Session 1912-1913. The next Meeting 

 of the Society for Scientific Business will be held on Tuesday, 

 October 28th, 1913, at half-past Eight o'clock p.m. 



The following papers have been received :^^ 

 1. D. M. S. Watson, M.Sc. 



Batrackiderjyeton lineatum Hancock & Atthey^ a Coal-Measure 

 Stegocephalian. 



