4 ARKIV FÖR ZOOLOGI. BAND 3. NIO 11. 



The photographic illustration (fig. 1) shows the character 

 of the specimen, V5 of the natural size. The accompanying 

 outline sketch (fig. 2) shows in the shaded portion, the ex- 

 tent of the specimen, the rest of the sketch being given to 

 show the general character of the type, and is based largely 

 on Limulus Walchi. 



Fig. 2. Limulus Nathorsti sp. nov. — Reconstriietion. 



As Limulus is an exceptionally interesting genus in its 

 structural and geological relatives, a brief statement of the 

 species is of in terest. Also a few of many measurements 

 recently made are given, as on these measurements part of 

 the above statements are based. 



Limulus priscus Munster, from the Muschelkalk, near 

 Bayreuth, is the oldest knovvn species of the genus. It is 



