290 Ortmann — Linuparus atavus. 



Art. XXXII. — On a New Species of the Palinur id- Genus 

 Linuparus found in the Upper Cretaceous of Dakota ; by 

 Arnold E. Ortmann, Ph.D. 



The Geological Museum of Princeton University has lately 

 acquired two unique specimens of a hitherto unknown fossil 

 species belonging to the family Palinuridse, which are not only 

 the first remains of this group of Decapoda found on the 

 American continent, but which — as regards the completeness 

 of preservation — surpass anything that is known of this group 

 from the European deposits. It is true, Palinuroid-Decapods 

 have been found in Europe, especially in England and Ger- 

 many, in great numbers, and the systematic relations of these 

 forms — as belonging to the family of Palinuridse — are beyond 

 any doubt. But there is hardly a form the affinities of which 

 to the living genera of this family have been ascertained : 

 accordingly, for most of them new genera have been created, 

 and although the old generic name of Palinurus has been used 

 for some of these European forms, there is nothing that indi- 

 cates a closer connection of this fossil Palinurus with the living 

 Palinurus " sensu strictiore." 



The American fossil here to be described not only shows all 

 the chief characteristics of the family, but it is so well pre- 

 served that the writer has been enabled to make out its generic 

 position, and he was exceedingly surprised that this fossil from 

 the Upper Cretaceous is congeneric with a species living now- 

 adays in the Japanese seas, namely with Palinurus trigonus 

 of de Haan,* the name of which stands at present as Linu- 

 parus trigonus (d. H.). The genus Linuparus created by 

 Gray in 1848 for this Japanese form is — as far as we know — a 

 monotypic genus, containing only that Japanese species just 

 mentioned. 



In order to make clear the systematic position of the new 

 fossil, it will be well to give a brief sketch of the generic 

 divisions of the family Palinuridse, as accepted in modern 

 zoology.f 



The family PalinuridsB contains seven recent genera : 

 Pali?iurellus Q Jasus, Palinurus, Palinustus, Linuparus, 

 Panulirus and Puerulus. Indeed, some of these genera have 

 not been admitted by some modern carcinologists, but I should 

 say that the differences of these genera are so striking, that 

 one would amply be justified in arranging them into three or 



* See de Haan, Fauna Japonica. Crust., decas 5, 1841, p. 157, pi. 39, 40. 



f Compare Ortmann, in Zoolog. Jahrb. Syst., vol. vi, 1891, pp. 13-38. I 

 should mention here, that some of the generic names used by me in this revision 

 do not comply with the rules of nomenclature accepted generally. Thus Avus 

 should be Linuparus, Senex should be Panulirus, and Puer ought to be changed, 

 since it has been preoccupied. (I should like to propose Puerulus for it.) 



