530 Dr. n. Woodward — Contributions to Fossil Crustacea. 



centimetres. Length of abdomen, including telson, 4^ centimetres ; 

 greatest breadth, 2^ centimetres. 



The first abdominal somite is narrow, and has a straight groove 

 running across it ; the mesial line is marked by a single tubercle. 

 The three following somites are also transversely grooved and have 

 two tubercles on the mesial line, one on either side of the groove ; 

 the epimeral pieces are small and somewhat acuminate ; the border 

 of each somite is marked by a rounded tubercle at its union with 

 the succeeding somite. The last two somites have only one central 

 tubercle, but are transversely grooved like the preceding. The 

 seventh somite or "telson" is nearly triangular in form, and is 

 marked by two converging ridges, and ends in a terminal spine. 

 The broad lateral swimming-plates are not preserved. 



This new species of Eryon serves as a link between the Litho- 

 graphic and Oxfordian Eryons above mentioned and those from 

 the Lias below, namely : — 



From the Upper Lias. 

 Hryon Hartmanni, Meyer, U. Lias, Wurtemberg. 



,, Edwardsii, Moriere, U. Lias, Calvados. 



,, Moorei, H. Woodw., U. Lias, Ilminster. 

 And from the Lower Lias. 

 Eryon Escheri, Oppel, L. Lias, Baden. 



,, antiqiius, Brodp., L. Lias, Lyme Eegis. 



,, Barroviensis, M'Coy, L. Lias, Barrow-on-Soar, etc. 



,, Wilmcotevsis, H. Woodw., L. Lias, Wilmcote. 



,, Urodiei, H. Woodw., L. Lias, Lyme Eegis. 



,, crassichelis, H. Woodw., L. Lias, Lyme Eegis. 



It will be seen at a glance that the 20 species we have enumerated 

 are nearly equally divided between the Upper Oolite (Kimmer- 

 idgian) and the Lias ; only one form, Eryon Ferroni, Etallon, 

 being found in the Oxford Clay of Oalmoutiers, Haute-Saone. 



Eryon Stoddarti most nearly approaches the Liassic species, in 

 which the cervical groove is always strongly marked, and also 

 the dorsal and branchio-cardiac ridges, characters not so strongly 

 defined and often absent in the species from Solenhofen. 



2. — Eryon Neocomiensis, Hohenegger (MS.). PI. XIV. Fig. 1. 



That distinguished palseontologist, the late Dr. Albert Oppel, in 

 his well-known " Pal^ontologische Mittheilungen " (Stuttgarl:, 

 1862), p. 9, observes on the geological distribution of the genus 

 Eryon, " that one finds this genus in the various strata from the 

 Lowest Lias to the Upper Jurassic beds ; we may therefore con- 

 clude that it enjoyed an unbroken existence through the whole 

 Jurassic period. And further, the Jurassic species of Eryon were 

 preceded by the still earlier Eryon {Bolina) Raihlanus, Bronn, sp., 

 from the Trias of Kaibl, Bohemia; and the Eryon (Tropifer) 

 IcBvis, Gould, sp., from the Rhaetic Bone-bed of Aust-passage, a 

 doubtful species at best. This genus then may be said to have 

 its beginning in the Trias, and to have continued through the 

 entire Jurassic period, and as far upwards as the Chalk, where it 

 becomes extinct." 



Dr. Oppel cites as his authority for the occurrence of Eryon in 



