556 H. Woodward — New British Fossil Crustacea. 



two lines in breadth, and two lines in height. Oyclus WrigJitii, 

 like C. hilohatus, has a mimetic resemblance to a Coleopterous Insect, 

 but the disproportion between the anterior and posterior divisions of 

 the carapace is even greater than in C. hilohatus, the anterior part 

 forming only one-fifth of the entire length. A narrow flattened 

 border encircles four-fifths of the carapace, the anterior fifth ap- 

 parently terminating abruptly at the margin without any border. 

 The dorsal ridge is prominent and broad, and extends from the 

 anterior to the posterior border, commencing as a narrow ridge be- 

 hind. It spreads out into two successive rounded expansions, and 

 again contracts somewhat before reaching the cervical furrow; in 

 front of which it again becomes much wider, then contracting slowly 

 towards the front. A somewhat triangular lobe flanks each side of 

 this dorsal line in front, whilst two nearly round lobes are placed, 

 one on either side of it, behind the cervical furrow. Nearer the 

 latero-anterior margin, two other rounded lobes are formed, one on 

 either side, by a branch of the cervical furrow. 



The two great latero-posterior lobes of the buckler have a single 

 corrugated ridge, commencing very faintly at the posterior dorsal 

 line, and running forward and curving around the sides of the cara- 

 pace, and becoming more strongly marked near the cervical furrow. 



The surface is smooth or slightly and very finely granulated. 



4. Cyclus HarTcnessi, H. Woodw., sp. nov., PI. XXIII., Fig. 6 and 6a. 



This elegant form approaches most nearly to G. radialis, but the 

 border of the shield appears to be wanting. Its length is 3^ lines ; 

 breadth three lines; elevation two lines. Another specimen measured 

 five lines in length ; S^ lines in breadth ; and three lines in height. 



In this species the usual cervical furrow, dividing the anterior from 

 the posterior portion, is indicated by a ridge which commences in 

 the middle of the shield where the raised dorsal line, instead of 

 terminating, diverges into two lateral branches directed obliquely 

 forwards, forming a Y-shaped elevation, from the branches of which 

 the cervical furrow is continued down to the latero-anterior border. 



From the margin of the dorsal ridge seven ribs take their rise, on 

 either side, and descend the steep border of the buckler towards its 

 rim, where, it is probable, they terminate in rounded exti*emities 

 as in Cyclus radialis (Fig. 2 and 2a.), but the matrix conceals it (see 

 Fig. Qa.). [I have, since the foregoing was written, been so for- 

 tunate as to detach a minute portion of matrix from one of the 

 specimens, and have satisfied myself that such is really the case, so 

 that Fig. 6«. needs to be added to along 

 the basal line as in the accompanying 

 woodcut.] These ribs are interrupted 

 near the crown of the shield by two 

 furrows, which encircle the posterior 

 three-fourths of the buckler, so as to 

 break up the ribs near the summit into ^V^"^ Sarhiessi, sp. nov. 



two sets of tubercles, the inner and (Side view, with margin restored.) 



ii]>y)er series being the larger, and the 



lower series the smaller; the surface of the ribs is finely granu- 



