LIMNIC YTHERE— CYTHERIDE A. 1 75 



4. LiMiNicYTHERE MONSTRiFiCA {Nomian). Plate II, figs. 8 a — d. 



1862. Cypris MONSTRIFICA, Norman. Ann. Mag. N. H., vol. ix, p. 45, pi. hi, 



figs. 4, 5. 

 1868. LiMNiCYTHERE — Brady. Monog. Rec. Brit, Ostrac, p. 420, pi. xxix, 



figs. 9—12. 



Valves, as seen from the side, oblong, subreniform, strongly spinous and tuberculated, 

 greatest height near the middle, and equal to about half the length. Extremities boldly 

 rounded, the anterior bearing on each valve a marginal row of about twelve small sharp 

 spines. Superior margin straight, angulated at its anterior extremity, whence it slopes 

 gently downwards and backwards ; inferior margin deeply sinuated. Seen from above, 

 compressed, irregularly ovate, lateral margins having two large spinous processes, and 

 several smaller spines and ridges ; extremities prominently mucronate. End-view sub- 

 quadrate, irregularly angulated. Valves closely punctate, furrowed across the middle j 

 one strong spinous tubercle on the anterior, and two on the posterior half of each valve ; 

 posterior portion also beset with numerous small spines. 

 Length, ^rd of an inch. 



Distribution. Recent. — England. 



Fossil. — England : Branston Fen, Lincolnshire. 



Genus 3. — Cytheridea, Bosquet. 



Valves unequal, the left mostly larger than the right, ovate or subtriangular, highest 

 at the anterior third. Surface smooth, or marked with scattered circular tubercles, 

 impressed puncta, or concentric furrows, anterior extremity rarely spinous, posterior some- 

 times bearing a single spine at its inferior angle. Lucid spots arranged in a transverse 

 row of three or four, with two detached, sometimes coalescent, spots in front. Hinge 

 composed of two crenated or " knurled " crests on the left (sometimes the right) valve 

 which articulate with corresponding depressions of the opposite valve. Upper antennae 

 very robust, mostly five-jointed, and bearing strong spines ; the last joint narrow and 

 elongated ; lower antennae four-jointed ; urticating setae long and slender, biarticulate. 

 Mandibles large and numerously toothed; palp three-jointed, and bearing a distinct 

 branchial appendage. The right foot of the first and second pairs in the male different 



