F. R. Coivper Heed — Cyclus in Irkh Carboniferous. 551 



IV. — Sedgwick Museum JS'otes. 



A New Species of Cfclus from the Caeboniperotjs Limestone 



OF Ikeland. 



By F. K. CowpER Reed, M.A., F.G.S. 



ASPECIMEjS" of Cyclus has lately been acquired from the 

 Carboniferous Limestone of St. Doulaghs, co. Dublin, which 

 indicates a new species, though it is allied to several which have 

 been described by Dr. Henry Woodward. The latter' gave in 1894 

 a review of our knowledge of this curious little Crustacean genus, and 

 his view that it is an Entomostracan and probably one of the 

 Phyllopoda has been generally accepted, though more recently^ (1905) 

 he has suggested that the members of this genus are but the larval 

 stages of Coal-measure Limuloids. 



Our specimen is in a good state of preservation and is perfect, except 

 round the anterior end, where the border is rather hidden by hard 

 matrix, but all the bosses on this part of the carapace seem to be 

 exposed. 



Cyclus simulans, sp. nov. 



Diagnosis. — Carapace oval in outline, convex, nearly hemispherical, 

 greatest height somewhat behind middle, posteriorly descending more 

 steeply to margin; surrounded by narrow border of regular width, 

 horizontally extended, with rounded raised rim and shallow marginal 

 farrow. 



Cyclus simulans, sp. nov. 

 Fig. 1. — Top view, x 12. 

 Fig. 2.— Side view, x 12. 



Anterior third of carapace elevated into regularly disposed 

 contiguous bosses, and divided from hinder part by curved transverse 

 cervical furrow. Four pairs of lateral bosses and one unpaired median 

 one present. Innermost posterior pair {h, h) subquadrate, in contact 

 in middle line and with median boss (»?j) in front and with cervical 

 furrow behind. Outer posterior pair (/g, /g) subtriangular, lying along 

 cervical furrow, wedged in between innermost posterior pair {h, l^) and 

 putermost posterior pair (Z^, l^), and in contact with anterior pair {l^) 



1 Woodward, Geol. Mag., 1894, Dec. IV, Vol. I, pp. 530-539. 



2 Bid., 1905, Dec. V, Vol. II, pp. 490-492. 



