ML'- 



REPORT — 1884. 



Woodward.' Thus an angular notch is often present in the forepart of 

 the fossil carapace. The median sutnrc has often been pressed inwards, 

 but more frequently it has parted, leaving the two larger parts of the test 

 separate. These remain as subtriangular plates, straight-edged but 

 angular on the inner margin, and either elliptically curved or almost 

 semicircular on the outer or free borders. They occur usually as black 

 <;arbonaceons films on the bed-planes of the sti-ata ; but sometimes they 

 have a somewhat corneous or chitinous appearance. 



A concentric linear ornament covers the whole shield ; num-rous 

 delicate ridges and furrows, following the curve of tlie outer margin, 

 converge and are concentric at the point where the doi'sal and nuchal 

 sutures meet, at or in front of the centre of the test. The style of orna- 

 ment is similar to that of the bivalve Estlieria, which shows a neat 

 arrangement of raised lines of growth, concentric with the umbones. 

 In the case of TJllipsocaris, even the interlinear sculpturing is present. 

 ('Geol. Mag.' Oct. 1882, p. 415.) If the two valves of Jhthcria, be laid 

 open, their surface would represent the shield of Apfycliojisig ; the open 

 angle then formed by their anterior margins would be analogous to tho 

 nuchal notch ; and for that of their hinder margins we may find an 

 analogue in the split posterior border of Di^terocaris and other forms 

 allied to Discinocaris and Apiycliopsis, 



1. Ajjf !/cJio2^st8 

 entre la 

 Boheme,' vol 

 ' Leth. Geogn 



prima, Barrandc, 1872, and var. Secunda. 

 Boheme et la Scandinavie,' 185G, p. G2. 



i. Suppl. 1872, p. 457, t. :];5, figs 1-21. 



187G, t. 10, f. ;{ct, 'M) (after Barra ue). 



' ParallMe 



Syst. Sil. 

 Koemer, 



This includes, according to ]\[. Barrande, both round and somewhat 

 obovate forms of the tripartite shield-like test, which both Barrande and 

 H. Woodward termed Aptijchopfiis independently in the same year (1872). 



Among the figures on plate IV.i of Syst. Sil. Boheme,' vol. i. Supplem. 

 circular forms are represented by figs. 1-8, 12-18, 20, and 21 ; and more 

 or less ohovate tests by figs 9-11 and 19. 



In tho British Museum (Natural History) are somi3 specimens labelled 

 by M. Barrande many years ago, as ' Aptijchits ? primus ' and ' AptijcJms ? 

 necunclus.' The former were decidedly obovate forms, when perfect, with 

 the two lateral moieties and the frontal (cephalic or rostral) in place; and 

 the latter (when perfect) were nearly or quite round. Evidently our 

 deceased friend had decided to group the two kinds together, by tho time 

 he published the Supplemental volume of his great work treating of these 

 Pbyllopods. The circular shields found in Bohemia arc chiefly from tho 

 schistose or slaty mudstone of Borek, Avith some from Litohlow and 

 Kozel — all in Etage •]'] e 1 ' ; and tlie ovate or obovate forms come from 

 the same geological origin, but in limestone at other localities, as 

 Butowitz, Slawick, and Wohrada, and rare at Kozel. 



Wo think that it will be advisable to distinguish the two forma, by 

 regarding one of them as varietal. Keeping M. Barrande's specific tarvn 

 Aptycliopsis prima, because his extensive series of specimens gave him 

 reason to regard the majority as being rather longer in tho fore and aft 

 diameter than in the transverse direction, and therefore not essentially 

 circular, wg may look upon the elongate and decidedly obovate forms as 



Quart, Jour. Geol. Sac. vol, xxii. p. C04'; and Geol. Mag. Dec. 2, vol. be. p. 387. 



