JACKSON, A NEW SPECIES OF FOSSIL LIMULUS. 5 



represented as far as known by only a single specimen, the 

 type, in the Munich Museum. It is a very small specimen 

 and possibly is not a mature individual. 



Limuhcs Walchi Desm. is the best known fossil species 

 and occurs abundantly in the Lithographic slates of Solen- 

 hofen and near by localities. Limulus 7naximus Munster, 

 from the same locahty, was described from a fragment of 

 the abdomen and telson. Five other species from the Litho- 

 graphic slates were described by Munster (in J. van der 

 Hoeven's, Recherches sur THistoire Naturelle et TAnatomie 

 des Limules, Leyden, 1838). These species are namely Li- 

 mulus oryiaius, intermedius, brevispina, brevicauda and stdcatus. 

 The types of the first four of these five species are in the 

 Munich Museum, and having recently studied them with care, 

 I feel very confident in saying tbat they present no distinc- 

 tive characters, and should be considered synonyms of 

 Limidus Walchi. 



Limulus Decheni Zincken, is from the Tertiary Braun- 

 kohlen formation of Germany. It is represented by the origi- 

 nal specimens at Halle, and by three magnificent specimens 

 in the Geologische Landesanstalt Museum in Berlin. These 

 latter have been recently described by Dr. Johannes Bohm 

 (Jahrbuch d. Kgl. Preuss. Geol. Landesanstalt und Berg- 

 akad. 1905). One of these specimens represents doubtless the 

 largest known Limulus. It is a cephalothorax which measured 

 on the curve of the test is 275 millimeters long and 470 mil- 

 limeters wide. On the basis of my studies of comparative 

 measurements, the whole animal must have been approxim- 

 ately 700 millimeters long. 



Of living species we have Limulus polypkemus Latr. 

 abundant on the atlantic coast of North America from New 

 England southward. A second living species is L. molucca- 

 71US Latr. 



With the present new form we know therefore five fos- 

 sil species, from the Triassic, Jurassic and Tertiary, but none 

 are yet known from the Cretaceous. In addition there are 

 two living species and possibly more. 



