Corresjjondence — E. Ray Lanhester. 



331 



The specimen figured is tlie first Pteraspidian fossil ever detected 

 in the numerous erratic Silurian boulders of Northern Germany, and 

 is not selected from among a great number of similar fossils. 



The two shields are not brought into contact accidentally, but 

 correspond to each other most clearly in their size and in their 

 mutual position. 



The other fragments of similar structure occurring in the same 

 piece of stone, probably represent the cornua and some of the scales. 



St. Petersbubs, MaG. F. SOHMIDT. 



iB/37 May, 187-3. 



NOTE ON HOLASPIS SERIGEUS. 



SiK, — WiU you kindly insert the inclosed outline sketch of a 

 lateral view of the shield of Holaspis, which exhibits the orbital 

 notch in a way which was impossible in the view of the upper 



0-] 



ICO 



Outline lateral view of the shield of Holaspis sericeiis. S. Kostrum. S. Spine. 0. Orhital 

 notch. Br, UepretBion corresponding to the comual perforation or branchial apertuie of 

 Fieraspis. 



