246 G. W. SHRFBSOLE ON THE VARIOUS SPECIES OF 



ment of the reverse face, showing, of course, no cells, and there- 

 fore valueless for specific purposes. It is not possible with such 

 material to determine the species. The species is lost ; for the most 

 that can be said of it is that, judging from the irregular character of 

 the fenestrules, as given in the sketch, it is the young stage of some 

 Fenestella. 



Fejj^estella Milleri, Lonsd., Murch. Sil. Syst. p. 678, pi. 15. fig. 17. 



This was intended by Lonsdale to be a new species. The type 

 specimen in the Museum is the conical base of apparently a Fenestella^ 

 with the coral growth incrusting and wholly concealing it, so that 

 not a cell-opening is visible. Lonsdale says that ^' the pores are 

 most apparent in the upper part," evidently because of the growth 

 around the base. The drawing shows this to be a species of Aulo- 

 pora. With the specimen and drawing both silent, and specific de- 

 tails absent, the species lapses as a matter of course. Prof. M'Coy en- 

 countered all this, and felt the impossibility of recognizing Lonsdale's 

 species, and, still unwilling that the name of one who did good work 

 at the Crinoids should be set aside, resolved to revive the name for 

 a newly found Bala species, a very much larger and diff'erent form 

 in every way, and one that does not occur in the Dudley beds. Some 

 fifteen years after the publication of the ' Silurian System,' Murchi- 

 son, in ' Siluria,' gives for the first time a sketch of the pore-face of 

 Fenestella Milleri, Lonsd. Meantime, as we have seen, Prof. M'Coy 

 had appropriated the name to another species from another horizon. 

 The question now arises, which of these species should retain the old 

 name — the one from Bala or that from Dudley, Lower or Upper Silu- 

 rian ? 



I think that Prof. M'Coy's species should still be known as 

 Fenestella Milleri from the circumstance that it was the first to be 

 adequately described, while Lonsdale gave a name only, and no 

 proper description of the species. Another reason for this decision 

 is that there is good reason for believing that Murchison's Fenestella 

 Milleri of 1854 is only Fenestella rigidula, M'Coy, without the 

 doubtful appendages on the keel. 



Eetepora iNFTTKDiBrLUM, Lousd., Murch. Sil. Syst. p. 679, pi. 15. 

 " fig. 24. 

 This is a true Fenestella. In mistake Lonsdale assigned it to 

 Retepora. He says of it, " The arrangement of the pores is similar to 

 that in Fenestella, but on the inner, and not the external surface." 

 As a rule the greater number of the Silurian Penestellidse have the 

 pore-face on the outside of the polyzoarium, but not aU. This 

 arrangement of outside pores prevails in those species having the 

 conical or cylindrical base. Others which are widely cup-shaped, with 

 a more open arrangement of the fenestrules, have the pores on the 

 inner side, in this respect corresponding to the Carboniferous species. 

 Lonsdale was clearly in error in giving generic value to the cir- 

 cumstance that in this particular Fenestella the cellules were on the 

 inner instead of the outer surface of the polyzoary. The generic 



