Vol. 54.] THE DECAPOD CETJSTACEA OF ENGLAND. 19 



first sight by the series of four bosses upon the mesogastric and 

 metabranchial lobes, arranged in a semicircle in front of the 

 cardiac lobe. 



Distribution. — Examples from the E,ed Crag (derivative) of Sutton 

 and Waldringfield are in the British' Museum, the Museum of 

 Practical Geology, the Woodwardian Museum, and the Ipswich 

 Museum. 



Deomilites Lamaeckit (Desmarest). 

 1858. Bell, Monogr. pt. i, p. 29 & pi. v, figs. 1-9. 



Supplementary. — The interorbital portion of the frontal border 

 is very prominent, triangular, and deeply grooved dorsally. Basal 

 joint of inner antennae robust. Epistome equilaterally triangular. 

 Sternal plastron narrow, longitudinally hollowed. Episternum 

 acutely pointed, half the length of the sternal plastron. Meropodite 

 of the chelse dentate on both borders. 



la the preface to Part II of his ' Monograph,' Bell suggests that 

 Dromilites may be the Tertiary representative of the Greensand 

 genus Homolopsis. Certainly aged individuals of Dr. LamarcJcii so 

 closely resemble specimens of Homolopsis Edwarclsii as to confirm 

 this view. The variation of character according to age and stage of 

 growth, to which Bell alludes in his description of Dr. BucMandi, is 

 equally remarkable as regards Dr. LamarcJcii. 



Distribution. — Specimens from the Bed Crag of Sutton and 

 "Waldringfield are in the Woodwardian and the Ipswich Museums. 



Genus Diaulax, Bell. 



Supplementary, — The two transverse sulci upon the dorsum of 

 the carapace, which suggested to Prof. Bell the name of this genus, 

 constitute a character which is not peculiar to it, but exists, more 

 or less distinctly marked, as a normal feature in other genera. The 

 anterior represents the cervical sulcus, and the posterior that which 

 separates the meso- and metabranchial lobes. This latter sulcus is 

 interrupted by the intervention of the cardiac lobe, as is accurately 

 represented in Bell's figure (pi. i, fig. 14). Bell mentions that it 

 is almost obsolete in many specimens of D, Carteriana. 



Diaulax Caeteeiana, Bell. 



1863. Bell, Monogi-. pt. ii, p. 6 & pi. i, figs. 14^16. 



Supplementary. — Carapace approximately hexagonal in outline ; 

 nearly half as high as wide ; considerably convex longitudinally in 

 the young, less so in the adult stage. Orbito-f rental border as wide 

 as the carapace is long. Eostrum slightly produced, pointed, broadly 

 triangular, with a median longitudinal depression. Orbits obliquely 

 oval, occupying the outer fourth of the orbito-frontal border ; a 

 shallow notch in both the upper and lower margins. Ophthalmic 

 peduncle constricted and granulated. Antero-lateral margin tren- 

 chant, meeting the thickened oblique postero-lateral at a considerable 

 angle. Posterior margin not so wide as the orbito-frontal. Epi- 

 branchial lobe tectiform, its outer portion forming the lateral angle. 



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