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 biscissus? 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 of P. 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 (1972: 91) 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. 1863. A monograph of the fossil malacostracous Crustacea of Great Britain. 
Part II, Crustacea of the Gault and Greensand. Monograph of the Palaeontographical 
Society of London. viii + 40 pp., 11 pls. 
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 geologischen Bundesanstalt, Wein, 81: 1-23. 
Forster, R. 1968. Paranecrocarcinus libanoticus n. sp. (Decapoda) und die Entwicklung 
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Paldontologie und historische Geologie, 8: 167-195, pl. 13. 
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144, pl. 17. 
Stenzel, H.B. 1945. Decapod crustaceans from the Cretaceous of Texas. Bulletin of the 
University of Texas Bureau of economic Geology and Technology, 4401: 401-476, 
pls. 34-45. 
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Magazine of Natural History, (10) 2: 456-462, pl. 13. 
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Palaeontographical Society of London. 114pp., 22 pls. 
