Palceozoic Bivalved Entomostraca. 401 



and an undulating surface of the valve behind, impressed with 

 one shallow, transverse, oblique valley in the young, and with 

 two such impressions in the old stage. They were collected 

 by Mr. G. C. Haswell in the Pentlands about or before 1866. 

 Size if X -^ inch, and smaller. 



10. Bolbozoe divisa^ Jones. (PI. XV. fig. 4.) 



Entomis cUvisa, Jones, Mem. Geol. Surv. Scotl. 32, 1861, p. 137; aud 

 Mouth. Microsc. Journ. vol. iv. 1870, p. 185, pi. Ixi. fig. 12. 



Entomidella divisa, Jones, Ann. & Mag. Nat, Hist. ser. 4, vol. xi. 1873, 

 p. 416; Woodward, Catal. Foss. Brit. Crust. 1877, p. 119. 



This was separated from Entomis because its sulcus did not 

 end at or near the centre of the valve, and it was placed with 

 Entomidella because of the length of the sulcus, reaching to 

 the antero-ventral border. Its direction, however, is not 

 directly across, like that seen in Entomidella, and I ought to 

 have referred the species to Bolbozoe in 1873, for tliis genus 

 can take it in (see above, p. 400). The flattening which our 

 figured specimen has received from pressure has greatly 

 lessened the prominence of the anterior swelling. Size of 

 valve f § X 1^ inch. 



Bolbozoe divisa has been found in dark grey micaceous 

 shale (Upper Silurian) at Cwm Craigddhu*, Builth, Brecon- 

 shire, and in the Lower? Ludlow formation at Ludfordf, 

 Shropshire. 



11. Entomidella Marrii (Hicks). (PI. XV. fig. 21.) 



Entomidella Marrii (Hicks), Jones, Report Brit. Assoc, for 1883, and 

 Geol. Mag. dec. 2, vol. x. 1883, p. 464. 



The genus Entomidella, instituted in 1873 (Ann. & Mag. 

 Nat. Hist. ser. 4, vol. xi. p. 417), has a good type in E. bu- 

 ^jvestis (Salter), Quart. Journ. Geol. Soc. vol. xxviii. 1872, 

 p. 183, pi. V. fig. 15 ; and now we have to figure another 

 species, already noticed at page 8 of the "Eeport on 

 Fossil Phyllopoda of the Paleeozoic Rocks," presented to the 

 British Association meeting at Southport in 1883, as having 

 been observed on a slab (in tire Cambridge University Mu- 

 seum) with Caryocaris, from the Upper- Arenig slates on the 

 NantUe tramway, at Pont Seiont, near Caernarvon. It has 

 the long, convex, pod-like shape of both Caryocaris Wriglitii 

 and Entomidella biqyrestis, associated, however, with the trans- 

 verse sulcus of the latter, from which it ditfers by being of 

 smaller size and thiinier at the ends. Surface smooth. It 



* Cat. Pal. Foss. M. P. G. 1878, p. 130 (ff). 

 t In Dr. Griffith's Culiectiou at Churcli iStrettou. 



