138 



of the mesogastric lobe, a large round one on the middle of the lobe 

 and a transverse pair of small ones to the rear; there is a large round 

 boss on the middle of each hepatic lobe and an outer small one, all 

 forming a transverse line with the anterior mesogastric boss. All the 

 raised areas of the cephalothorax have well-separated small granules 

 between the bosses. 



Discussion. The holotype is incomplete, lacking nearly all of the 

 frontal and lateral margins. The arrangement of the lobes, except for 

 the urogastric which is weakly bilobed longitudinally rather than 

 divided transversely into two bars, is close to that of R. polyakron 

 Stenzel and R. woodsi Withers. The epigastric, mesogastric and 

 hepatic bosses also are similar in disposition. It is highly probable 

 that the present species is a primitive Rathbunopon but in the 

 absence of evidence of the characteristic orbits attribution must 

 remain uncertain. There is some resemblance to the fragmentary 

 holotype of the Hauterivian Homolopsis tuberculata Van Straelen, 

 1936, which may also be a Rathbunopon. 



Paranecrocarcinus biscissusl Wright & Collins, 1972 



Figs 10, 15 



An incompletely preserved internal mould from the Cenomanian of 

 Whitcliff, Seaton, Devon (BMNH IC 10) has the same arrangement 

 of outer orbital spines and fissures as P. biscissus Wright & Collins 

 (1972: text-fig. 10b) and a multiplicity of small tubercles, including 

 three on the urogastric lobe. However the number and arrangement 

 of the other tubercles is not exactly as in the holotype off! biscissus. 

 The present specimen has an estimated breadth of 9 mm, against 12 

 mm of the holotype, and is probably an earlier moult of the same 

 species. 



Paranecrocaricinus digitatus Wright & Collins, 1972 



Fig. 11 



A further specimen from Wilmington (BMNH IC 5) confirms the 

 restoration given by Wright & Collins (1972: text-fig. 10a). 



Hemioon elongatum (Milne-Edwards, 1862) 



A poorly preserved specimen has been found in Bed C of the Devon 

 Cenomanian Limestone, thus extending the range of this species to 

 the Calycoceras guerangeri Zone of the Upper Cenomanian. 



C.W. WRIGHT 



Withersella crepitans Wright & Collins, 1972 Figs 12, 16 



Wright & Collins ( 1 972: 9 1 ) established W.crepitans on the basis of 

 14 specimens of a delicate crab from the Crackers Bed at Atherfield. 

 They gave a restored diagrammatic view of the cephalothorax 

 showing the frontal margin with broad rectangular indentations and 

 teeth. Subsequently a specimen was found (BMNH IC 15) with the 

 left frontal margin almost perfectly preserved indicating that the 

 diagram in Wright & Collins was based on a broken edge of the thin 

 carapace. 



The actual frontal margin (Figs 12, 16), is bounded by large 

 outer orbital spines and is rather concave, interrupted only by 

 paired oblique supraorbital fissures and a marked inner orbital 

 spine on either side of a bifid rostrum. In effect the front of 

 Withersella is extremely close to that of Carcineretes walcotti 

 Withers, except for the greater projection of the rostrum in 

 Withersella, thus confirming the attribution to Carcineretidae by 

 Wright & Collins, which Glaessner (1980: 180) had regarded as 

 unconvincing. Also, the front of Withersella more closely resem- 

 bles that of Binkhorstia than was apparent in 1972, although there 

 are significant differences in the latter's peculiar spatulate rostrum, 

 third supraorbital fissure and less oblique fissures (Collins, Fraaye 

 & Jagt. 1995: figs 12a-c). 



REFERENCES 



Bell, T. 186.^. A monograph of the fossil malacostracous Crustacea of Great Britain. 



Part II, Crustacea of the Gault and Greensand. Monograph of the Palaeontographical 



Society oj London, viii + 40 pp., 1 1 pis. 

 Collins, J.S.H., Fraaye, R.H.B. & Jagt, J.W.M. 1995. Late Cretaceous anomurans 



and brachyurans from the Maastrichtian type area. Acta Palaeontologica Polonica, 



40: 165-210, 12 figs. 

 Glaessner, M.F. 1931. Geologisches Studien in des aiisseren Klippenzone. Jahrbuch 



der geotogischen Bundesanstalt. Wein, 81: 1-23. 

 F6rster,R. X'ibi.ParanecmcarcmusUbanoticusn. sp. (Decapoda) und die Entwicklung 



der Calappidae in der Kreide. Mitteilungen der Bayerischen Staatssammlung fur 



Paldontologie und historische Geologie, 8; 167-195, pi. 13. 

 1970. Neue Decapoden Reste aus der Oberkreide von Mojambique, 



Norddeutschland und den bayerischen Alpen. Paldontologische Zeitschrift, 44: 1 34— 



144, pi. 17. 

 Stenzel, H.B. 1945. Decapod crustaceans from the Cretaceous of Texas. Bulletin of the 



University of Texas Bureau of economic Geology arui Technology, 4401: 401^76, 



pis. 34-45. 

 Withers, T.H. 1928. New Cretaceous crabs from England and Syria. Annals and 



Magazine of Natural History. (10) 2: 456^62. pi. 13. 

 Wright C.W. & J.S.H. Collins, 1972. British Cretaceous Crabs. Monograph of the 



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