PLATE I. 



Lover Oi-ihivicinn AntJirrjia (1-0) find C'rplialnpniln (10); rdJinfzf Lirnextonr. Upper 

 < h'diivlclaii BracJiiojioiJa PcJcei/inuld ami Tr/liililta: i][ar]i iiil:<i}i. Li nusloiir. 



Dratrings hy K. «'. Liu i^i]^^) Pholofirapli^ by T. L. Loo i^MM) 



Fig. 1. Aiv]i.,roryatJnis cJiiJiJicriftr Grabau p, 12 



la. Mold of part of interior of caliculum with weathereil section near the upper edge 



of the caliculum. Natural size, 

 lb. Photogrupli of partial section of caliculum 50 ram. below preceding; nearly natural 



size. The right and left sides are reversed with reference to fig. la, Lower 



Ordovieian Peilintze limestone, Siiih-^lun-Chai, Chihli. CCoU. V F. Mathieu, 



Cotype G. S. Ch. Cat. No, 75). 



Fig. 2. AirJiaoryatJiiis vhililicnsc (irabau p. 12 



Photograph of polished section of a compressed caliculum same horizon and locality. 

 Natural size. (Cutype Coll. F Y Mathieu, (_;. S, Ch. Cat. No. TCl) ■ 



Fig. 3. Arcliiiocyatlius clrililieiixe Grabau p. 12 



oa. Piiotograph of thin section of a nearly circular caliculum. Natural size. 

 3b. A small portion photographically enlarged X IH; same horizon and locality. 

 (Cotype Coll. F. F. Mathieu, G. S. Ch. Cat. No. 98). 



Fig. 4. OrtJiis ciiUiyrfDinna var. iirtliitmliiinilcK von Buch (de Verneuil) p. 15 



4a brachial-, 4b pedicle-, 4c side-view of a, small fragmentary specimen X 3; Alachia- 

 kou limestone, Chao-Kou-Chuang, Chihli province. (G. S. Ch. Cat. No. 94). 



Fig. 5. OrtJiis roUigiamvia var, urfliamiionifcs von Buch (de Verneuil) p. 15 



5a pedicle-, 5b brachial-, 5c lateral-, 5d frontal-views of a larger, somewhat doj^torted 

 and more nearly complete specimen. X 2. (In 4d the upper valve i-s the brachial, 

 which appears as the deeper of the two because of the position in which the 

 specimen is drawn). Same horizon and locality. (<!. S, Ch. Cat. No. 93). 



Fig. 6. Sli'oplniniciia cf. iiinin'cdn (.Shepard) p. 17 



Part of pedicle valve, with outline restoied X 3. 



Upper Ordovieian, Machiakou limestone, Chao-Kon-Chuang, (<1. S. Ch. Cat. 



No. 109). 



Fig. 7. C'lc iioildiifa Kym iiifii'icd (irabau p. 19 



Interior view of a right valve, showing the hinge line, (with tlie teeth somewhat 

 too clearly represented), the muscular scars and anterior muscular ridge The 

 ventral margin is imperfect. Enlarged twice Machiakou limestone, Tangshan, 

 Chihli. (Holotype G. B. Barbour Coll. (4. S. CI,. Cat. No. 51) , 



Fig. 8. AKctpliiiH hii'lrmi Lorenz p, 93 



An imperfect pygidium, enlarged X 2. showing broad ringed axis, and concave 

 marginal rim. Machiakou limestone, Chao-Kou-Chuang, Chihli. (G. S. Ch. Cat. 

 No. 92) . 



Fig. 9. AKpliii^ hiilniii Lorenz p. 93 



Another jiygidium from the same horizon and localitj' as the preceding but 

 exfoliated, showing narrow axis, X 2. (G. S. Ch. Cat. No. 110). 



Fig. 10. CliiJilioceivi.'i luiUiniii (irabau p. 48 



Apertural view of the siphuncle shown in the right hand figure of Plate V. to show 

 the main and lateral alveoli. The specimen is slightly crushed, and is weathered. 

 Lower Ordovieian Peilintze limestone, Sliih-Mun-Chai region, Chilili. ((i. S (4i 

 Cat. No. Ill), 



— 1(12 - 



