Basinotopus lamarckii [Dromilites lamarckii]

Dromilites lamarckii (Desmarest, 1822), Inachus lamarckii Desmarest, 1822 Inachus spec Desmarest, 1822 are all synonyms of Basinotopus lamarckii. 

Basinotopus lamarckii can often be found across many of the London Clay sites, both in Kent and Essex. These sites include Allhalllows, Sheppey, Maylandsea, Aveley Number 2 Pit, Tankerton, Butts Cliff, and Seasalter. It has been recorded at divisions A3, B1, B2, C, D, E, U and L. 

It can be easily identified from its distinctive carapace as seen below.