The mod 2 cohomology of the infinite families of Coxeter groups of type B and D as almost Hopf rings

We describe a Hopf ring structure on the direct sum of the cohomology groups ${⨁}_{n\ge 0}{H}^{\ast }(W_{B_n};{\mathbb{F}}_2)$ of the Coxeter groups of type $B_n$, and an almost-Hopf ring structure on the direct sum of the cohomology groups $\bigoplus_{n \geq 0} H^* \left( W_{D_n}; $\mathbb{F}$_2 \right)$oftheCoxetergroupsoftype$D_n$, with coefficient in the field with two elements ${\mathbb{F}}_2$. We give presentations with generators and relations, determine additive bases and compute the Steenrod algebra action. The generators are described both in terms of a geometric construction by De Concini and Salvetti and in terms of their restriction to elementary abelian 2-subgroups.