Carapace medium, 0.65-0.75 mm long, strongly inflated, broadly ovate in lateral view. Caudal process above mid-height position. Fused zone narrow. Female slightly higher and larger than male. Mandible coxa of moderate length. Knee seta of second leg short and slender. Male copulatory appendage with a rounded basal capsule and two distal processes, the anterior one bicuspate anteriorly with a lamellar extension posteriorly, the posterior one long and narrow (P. bradyi 5 ). Living specimens strongly pigmented, olive- or chestnut-brown.
Commonly found amongst littoral and shallow sublittoral algae.
Sars (1928) established this species for P. obliquum sensu Brady (1868b). As far as we can ascertain the true P. obliquum Sars (1866) does not live in British waters, and most material bearing that name in the Brady & Norman collections is referable to P. bradyi (but see also Remarks on P. nealei). P. bradyi is easily distinguished from most other British species of the genus by its strongly inflated carapace and (when alive) its characteristic colour. P. nealei, although similar in shape, has a more elongate carapace, more pronounced sexual dimorphism and very different male copulatory appendages.
British Isles, Norway, Sweden, N France.