Yol. 54.] THE DECAPOD CRUSTACEA 6E ENGLAND. ' 35 



Genus Ehachiosojvta, "Woodward. 



E-HACHiosoMA BispiNOsUM, Woodward. 



1871. Woodward, Quart. Journ. Geol. Soc. vol. xxvii, p. 91 & pi. iv, fig. 3. 

 1873. Woodward, ibid. vol. xxix, p. 26 & pi. i, figs. 1-6. 



Description. — Carapace about one-fourth wider than long (ex- 

 cluding the lateral spines). Orbito-frontal border rather more 

 than a third the width of the carapace ; the interorbital portion 

 ■quadridentate. Eostrum slightly bifid. Orbits nearly round, with 

 two notches in the upper and one in the lower margin. Antero- 

 lateral border with four pointed processes, the first three gradually 

 increasing in size ; the portion of the border between them flattened 

 into a trenchant edge which is indented by a sharp cleft ; the 

 fourth, or epibranchial, process prolonged into a spine, the length 

 of which, in some specimens, is equal to half the width of the cara- 

 pace. Postero-lateral border thickened. Posterior border rather 

 wider than the orbito-frontal ; the postero-lateral angles slightly 

 produced. Dorsal surface minutely granular in well-preserved 

 specimens. An areolar tubercle occurs on each protogastric lobe, 

 two (or three) on the mesogastric, one near the base of the long 

 epibranchial spine, and an oblique longitudinal series of three on 

 each metabranchial lobe. The cardiac lobe bears a single median 

 tubercle. Two minute punctures marking the attachment of the 

 posterior gastric muscles are noticeable behind the mesogastric 

 lobe. The several normal dorsal regions are defined by shallow 

 depressions. 



Pemale abdomen seven-jointed. In the male the fifth and sixth 

 segments are coalescent. Telson small. Sternum broadly ovate ; 

 endopodite of tbe external maxilliped twice as wide as exopodite, 

 furrowed longitudinally. 



Buccal opening large. Chelae nearly equal in size ; hand smooth, 

 approximately twice as long as wide, ovate in section ; palm less 

 convex than the dorsum. Pingers slender, rather shorter than the 

 hand ; prehensile border serrated by eight to twelve teeth. All the 

 posterior pairs of limbs are well-developed and nearly equal in size, 

 the last pair being as large as, or rather larger than, the penulti- 

 mate, as in most Portunidse. Width of carapace (excluding the 

 epibranchial spine) =from 25 to 50 mm. 



Distribution. — I have examined upwards of twenty examples, 

 all of which were obtained from the London Clay of Portsmouth. 

 Specimens are in the British Museum, and a large series in the 

 Woodwardian Museum ; a single example, labelled ' Psammocarcinus^ 

 is in the Manchester Museum. 



(ii) Subfamily Cancridae. 

 Genus Act^opsis, Carter. 

 AcT^opsjs WiLTSHiEEi, sp. nov. (PI. II, fig. 3.) 



Description. — Carapace approximately hexagonal in outline, 

 slightly and equally convex, both transversely and longitudinally ; 



d2 



