FOEMATIONS AIS-D FOSSILS OP SOUTH MANCHUBIA 87 



rather densely with the calcareous deposit, leaving only small spaces 

 here and there. 



The specific name is given in honor of G. Hata, a geologist of 

 the geological institute of the South Manchuria Eailway Co. 



Comparisons. — This species is closely related to Armenoceras tani 

 (Grabau), but differs in having a larger concavity of the septa and 

 a more excentric siphuncle. 



Formation am,d locality. — Middle Ordovician, Ssuyen formation: 

 Lower fossil horizon of the black banded limestones, just north of 

 the Pen-hsi-hu colliery, Liao-tung, Manchuria. 



Holotype.—\].^.'^.'M.. No. 83715. 



ARMENOCERAS HARIOI (Eobayashi) 

 Pl-ATE 16, FiGUEE 1 



1927. Actinoceras harioi Kobayashi, Jap. Journ. Geol. and Geogr., vol. 5, no. 4, 

 p. 196, pi. 20, fig. 12; pi. 21, fig. 9. 



Description. — A fragmental specimen, 25.5 mm long, enlarges 

 slightly from the base to the top. The cross section of the conch, 

 apparently, was laterally depressed, while that of the siphuncle was 

 circular, but most of the dorsal side has weathered away. The si- 

 phuncle is located very excentrically. The number of camerae in a 

 length equal to the diameter of the conch equals about 10. Where 

 the lateral diameter of the conch is 15.5 mm, the concavity of the 

 septa is 2 mm, the length of the camerae is 1.4 mm, and the maxi- 

 mum diameter of th^ segments of the siphuncle 3 mm. There are 

 no traces of the septal necks at the inner margins of the septa, which 

 are combined with both upper and lower connecting rings at acute 

 angles. The calcareous matrix is slightly developed in the camerae 

 of the apical part of the shell, while it fills very densely the camerae 

 of the older part. 



Formation and locality. — Middle Ordovician, Ssuyen formation: 

 In the lower fossil horizon of the gray banded limestone beds, on 

 Fu-chin-kou ridge, southwest of Miyanohara station on the Antung- 

 Mukden line, Manchuria. 



Plesiotype.—'U.^:^M. No. 83T16. 



ARMENOCERAS HAYASAEAI, new species 



Plate: 18, Figtjees 6, 7 



Description. — The holotype is 97 mm long, enlarging from a lateral 

 diameter of 13 mm near its base to 20.5 mm at a point 42 mm farther 

 up, the apical angle being 10°. The cross sections of the conch and 

 the siphuncle are somewhat depressed. A small portion of the ven- 

 tral side is weathered away. Eight camerae occupy a length equal 

 to the lateral diameter of the conch. Where the diameter of the 



