ENTOMIS. 85 



1. Entomis concentrica (De KonincJc), 1841. PI. IV, figs. 22, 25a, 250. 



Cypkidina concentrica, De Koninck, 1841. Nouv. Mem. Acad. Roy. Brux., vol. xiv, 



p. 18, fig. 10; 1844, Descript. Anim. 

 foss. Terr. Carb. Belg., p. 587, pi. 52, 

 figs. 4, 5. 

 Cythere concentrica, Bvpont, 1863. Bull. Acad. R. Sc. Brux., ser. 2, vol. xv, 



p. 110. 

 Entomis — Jones and Kirkby, 1864. Neues Jahrb. fiir Min., &c, Jahrg. 



1864, p. 54 ; Canad. Nat. Geol., 

 n. s., vol. i, p. 237. 



This Belgian species has an oblong carapace with rounded ends, like a haricot-bean. 

 The lower margin has an elliptical curvature in Prof. L. De Koninck's fig. 5, but is 

 nearly straight in our fig. 2ba. 



mm. mm. Proportions. 



Length 6-25 5-25 . 25 21 



Height 3-5 3 . 14 12 



Thickness 3 2 -5 . 12 10 



Each valve is sculptured with concentric elliptical lines, like the minute plicae or ridges 

 of the skin on the inside of the human finger-top. These delicate wrinkles, however, are 

 interrupted by the strong transverse sulcus near the middle of the valve, so that the hinder 

 moiety of the surface has a complete and nearly horizontal pattern of elliptically concentric 

 rugae, and the lowest or most ventral of these curve forward and upward on the anterior 

 moiety of the valve, and converge on its antero-dorsal margin, where the sulcus or 

 nuchal furrow begins. 



The specimens here figured were given to us by our friend the late M. J. Bosquet, of 

 Maastricht, well known for his palaeontological researches in Holland and Belgium. 



Pig. 22 is a cream-coloured carapace ; and figs. 25«, 250, represent a yellowish-grey 

 internal cast, showing a strong sulcus, and retaining a faint trace of the external orna- 

 ment. Pig. 22 gives a dorsal view (in outline) of the two valves, opened, but still 

 touching along the hinge-margin. 



This species is said to be very rare in Belgium. We have not met with it in 

 Britain. 



2. Entomis biconcentrica, Jones, 1S70. PI. IV, figs. 23a, 230, 26a, 26d. 



Entomis biconcentrica, Jones, 1870. Monthly Microsc. Journ. for October, 1870, 



vol. iv, p. 185, pi. lxi, figs. 13 a, b. 



This is also fabiform, oblong in outline with rounded ends ; and it has a strong 

 sulcus, as in E. concentrica. Its sculpturing, however, though of the same character, 



