(hi) 14 Palfeontologia Sinica Ser. B. 



ed from th? plicated part by a U-shape groove. The surface is covered by about 

 twenty angular and rather simple plications with wider interspaces and intercala- 

 tions and branchings here and there. 



Measurements : 



Greatest width = 6 mm 



Height =4 ,, 



Proportion of height to width = 1.50 



On the same slab is another specimen of the same sj^ecies. The valve is a httle 

 more convex than No. X 201.. The rostral cone shown in the interior mold is larger 

 and is separated from the plications by two more or less parallel grooves which do 

 not meet anteriorly and thus become U-shaped as in the case of No. X 209. The 

 grooves become less and less deep as the}' recede from the beak, till in the anterior 

 part of the cone there remains only a trace of them. 



Remarks: This species is very much like Orthis callujratni/ui Dalnian, var? 

 Reed (figs. 16-19, pi. V, the Urdovician and Silurian Brachiopoda of the Girvan 

 District). It differs in not having fine longitudinal lines within the interspaces of 

 the plications and faint transverse lamellose striae. Owing to Reed's uncertainty 

 with regard to his specimen a new specific name is here proposed. As noted by 

 him this may be simply the young of Orthis calligramma Dalman, but for the pre- 

 sent we will leave it under a distinctive designation. 



Horizon and Locality: Occurs with the preceding. Coll. C. C. Yii. (Scr. 

 Nos. X 201, X 209; Cat. Nos. 3375, 3376). 



8. Orthis calligramma Dalman. var. intercalare Chang (var. nov.) 



PI. II, Figs. la-b, 2a-b, 3a-b, & 4a-b. 



This species is represented by a number of molds of both the pedicle and the 

 brachial valves. It is wider than high and has a hinge line which is a little less 

 than the greatest width and the frontal margin regularly curved. The pedicle 

 valve is gently convex, the l)eak being slightly incurved. The rostral cone is pear- 

 shaped and marked off from the plicated portion b\' two crescentic grooves which 

 become gradually less deej) as they pass farther from the beak. On the surface 

 of the cone are found seven longitudinal raised lines, the middle one being stronger 

 than the rest and seemingly continuous with the median plication. The brachial 

 ^'alve is flat. A triangular rostral cone with a groove occu})ied by a tongue- 

 shaped })rrjoction which docs not reach the to}), extends beyond the hinge line. It 



