6^2 



BRACHIOPODA. 



The Bracliiopoda, whidi were formerly very numerous, both in genera, 

 species, and individuals, are now represented by a little over a hundred 

 species, distributed among sonic fifteen or sixteen genera. 



Ji.7. lO.—Spmfersulcatus. A sppcimen, natural 

 size, and an enlargement of tlie middle part 

 of the binge-area (/I.) of the ventral valve, 

 showing the delthvrium almost closed by 

 two deltidial plates (ii.), so that only a small 

 foramen (i?.) remains. 



Fig. n.— Lophophore supports in MageU 

 lania (m.)an(l Atrypala.). m.s., median 

 septum; c , crura; c.p., crural processes; 

 ,7.p. , jugal processes; d.l., descending 

 lamella a.l.. ascending lamella ; y.i., 

 primary lamella ; s.c, spiral coils. 



The Brachiopoda have often been grouped together with the other forms 

 that have a lophophore (Bryozoa, etc") under the name Molluscoidea (mol- 

 lusc-like). But, while they certainly are not related to the Mollusca, it is 

 very doubtful how far they are allied to these other forms. It is therefore 

 safer to keep them as a separate group of the animal kingdom. 



