CALYPTOCARIS RICHTERTANA. 183 



margin; those on the middle and dorsal regions are straight. No gastric nor 

 optic ridges are visible. 



The transverse fracture shows the thinness of the compressed fossil (scarcely one 

 millimetre). 



The former reference of this little fossil to Dithyrocaris is probably incorrect, 

 as intimated in the ' Gebl. Mag.,' 1874, p. 109, although its longitudinal riblets 

 are not without analogies in D. Belli (PL XVIII, fig. 8, and < Geol. Mag.,' 1871, 

 p. 106, pi. iii, fig. 5). Nor does it fall in with the Ceratiocaridx, although it has 

 some likeness to Ceratiocaris Salteriana, J. & W., ' Monograph,' 1888, p. 55, 

 PL VII, figs. 1, 2, 3. The ornament of several parallel, slightly curved ridges 

 along the lateral moieties of the test are seen in Packard's figure of Lepidurus 

 Colleii, 'North American Phyll.,' pi. xv. fig. 2. 



Tropidocaris and Bhinocaris l (other Phyllocarids related to Ceratiocaris) have 

 carapace-valves bearing longitudinal riblets, but much coarser than those of 

 either C. striata or D. Belli, and the valves themselves differ in shape considerably 

 from those of the two latter forms. Compare also Btychocaris, Novak, ' Sitz. 

 Bohm. Ges. Wissensch.,' 1885, p. 345, pi. o, figs. 4 — 8, with its numerous strias 

 and pitted interspaces. 



This unique specimen (Mus. Geol. Surv. Scot, m 576 a, F ^f , No. 15) was 

 collected from a " greenish-grey " (now reddish), flaggy, calcareous shale of the 

 Lower Red Sandstone, of the Calciferous Sandstone series at the Carmichael 

 Burn, near the Manse, four and a half miles south-east of Lanark. 



We have to notice that a granular band, 1 mm. wide, is associated with the 

 border of the valves, looking as if some soft material had been squeezed out from 

 between the valves, and had helped to form a concretiouary border there. It is 

 included in the left-hand margin in the figure of the carapace. 



2. Calyptocaris? Richteriana, sp. nov. Plate XXII, fig. 2. 



Size. — Length 6 mm. ; width 3"2 mm. Imperfect. 



Characters. — This figure is copied from a sketch made by our friend Mr. 

 J. W. Kirkby, who recognised it (in 1864) in some hard red shale of the so- 

 called " Cypridinen-Schiefer " (Entomis-shales), sent by the late Dr. R. Richter 

 from Saalfeld, Sachsen-Meiningen. 



The surface is coarsely striate, and has three longitudinal riblets ; unfortu- 

 nately the outline is imperfect, and there are no characteristic cephalic eminences. 

 It may indeed have some relationship with Chsenocaris as well as with Calyptocaris. 



It is here introduced as indicative of the wide range of the costulate forms. 



1 Hall and Clarke, ' Palaeont. New York,' vol. vii (1888), pp. 184, 195, pis. xxx and xxxi. 



