I7ir 



On the dorsal mould there are seen the impressions of adductors and the- 

 edge of the median septum. On thi inside both the valve seem to be pro — 

 vided with numerous pits, suggested by the very great number of warts om 

 the surfe.ce of the impression. 



Dimensions : — • i 



Length. . Width. Thickness. 



25 mm. 28 mm. 14 mm. 



, 30 „ 35, : „ 



30 „ 36 „ 18 „ 



33 3S 19 „ 



Locality : — Ning-chang, Han-chang-fu, prov. Shen-hsi. 

 At this locality Atrypa 7-ciicularis var. riclitliofcni, RJiynchonclla paral— 

 leLepipcda and some other fossils were found in association with the present 

 variety of A. reticularis. Von Richthofen's collection at Lung-tung-pei may 

 also have originated here, for he did not collect in situ at that locality, which.- 

 is very near to Ning-chang. 



Geological Agfe : — Middle Devonian. 



Atrypa reticularis Linne, var. auriculata nov. 

 PI. XXIII., Figs. 2 and 3. 



It is a very popular opinion among palaeontologists that Atrypa reticula- 

 ris is one of the most variable species of Bra.chiopods. There is indeed a large; 

 number of varietal forms of the species, each of which is likewise not very 

 constant in shape. The present writer, however, does not know of any re- 

 corded form that is comparable with the one from China now to be described. . 

 The species Atrypa reticularis and its varieties have been so well studied, 

 that it may not seem proper to add to ti'.em one more new variety. This the 

 writer himself acknowledges, and does not mean in describing the form to 

 insist upon the independence of the new varietal name. Had he been able to 

 examine many specimens of the species and its varieties from various corners 

 of the world, he might have been able to find some intermediate types linking: 

 the present fossil to the type species or to some one of its varieties. 



