414 Prof. T. Rupert Jones on the 



the Pentland Hills, Scotland (Messrs. Haswell and Brown's 

 Collections). 



The surface of the valves in some species is ornamented 

 with delicate riblets, transverse, longitudinal, or concentric. 



As far as the shape of the carapace is concerned, Entomis 

 stands in the same relation to CyprideUa of De Koninck as 

 Poly cope of Sars to Cypridina of Milne-Edwards, the anterior 

 notch having disappeared in both Polycope and Entomis. The 

 animals^ however, may have respectively differed very much ; 

 for Polycope and Cypridina belong to different families^ and 

 the deep nuchal furrow in Entomis , far more impressed than in 

 CyprideUa^ was probably in direct relation with the structure 

 of its internal organs, under modifications not present in other 

 genera. 



The physiological meaning of the nuchal furrow in these 

 Entomostraca is not understood. It is faintly indicated in 

 Philomedes and Halocypris ; it is stronger in Pleopsis and 

 Paphnella, belonging to quite another group of Entomostraca. 



The known Entomides are : — 



1. Entomis concentrica (De Koninck), 1841. 



Cypridina concentrica. De Kon. 1841. Mem. Acad. Koy. Belg'. vol. xiv. 

 'p. 18, f. 10; 1844. Desc. Anim. foss. Terr. Carb. Belg. p. 687, pi. 52. 



fip:s. 4, 5. 

 Cijthcre concentrica, Dupont, 1863. Bull. Acad. K. Sc. Belg. ser. 2, 



vol. XV. p. 110. 

 Entoynis concentrica, Jones & Kirkby, 1864. Neues Jahrb. fiir 1864, p. 54 j 



Canad. Nat. Geol. n. s. vol. i. p. 237. 



Lower Carboniferous : Belgium. 



2. E7itomis serratostriata (G. Sandberger), 1842. 



Cypridina serratostriata, G. Sandberger, Leonh. u. Bronn's Jahrb. 1842, 

 p. 226 ; Jahrb. Ver. Nat. Nassau, Heft ii. 1845, p. 121, pi. 1. fig. 6 ; 

 G. & F. Sandberger, Verstein. Rhein. Schicht. Nassau, 1850, p. 4, 

 pi. 1. fig. 2. From the Cypridinen-Schiefer of Nassau. 



Cypridina serratostriata, F. A. Romer, 1854. Palseontogr. iii. Beitr. 

 geol. Kennt. nordw. Harzgeb. p. 42, pi. 6. fig. 15. From the Cypri- 

 dinen-Schiefer of the Harz. 



Cypridina ? serratostriata, Jones, in Morris's Catal. Brit. Foss. 1854, 

 p. 104. Devonshire? 



Cypridina serratostriata, Richter, 1856. Denkschr. Akad. Wien, vol. xi., 

 Beitr. Pal. Thiir. Waldes, p. 35, pi. 2. figs. 20-29. Thuringia. 



Cypridina serratostriata, Ferd. Romer, 1856. In Bronn's Leth. Geogn. 

 3rd edit. vol. i. p. 532 (not including the synonyms). Germany. 



^'Entomis of the Cypridinen-Schiefer," Jones & Kirkby, 1863. Geolo- 

 gist, vi. p. 460 J 1864. Rep. Brit. Assoc. Newcastle, 1863, Trans. 

 Sect. p. 80. 



Devonian : Europe ; England {fide Ferd. Romer & Godwin- 

 Austen*). 



* Quart. Journ. Geol. Soc. vol. xiii. p. Ixxxix. 



