Original description: Test spindle-shaped (conical when broken), with five to seven post-abdominal chambers. Cephalis small, hemispherical without horn. Chambers increasing gradually in length, rapidly in width as added. Final post-abdominal chamber terminating in narrow tubular extension. Test wall double-layered. Inner latticed wall consisting of regularly aligned square to rectangular pore frames. Outer layer of cephalis imperforate, covered with layer of microgranular silica. Thorax and subsequent chambers with massive costae and thin transverse bars forming rectangular pore frames overlapping on inner layer. Bars of outer layer fragile, often broken and leaving short remnants at costae. About eleven to thirteen costae visible laterally. Pore frames gradually increasing in size from thorax to final post-abdominal chamber then decreasing in size distally.

Original remarks: Broctus ruesti n. sp., di&64256;ers from B. sp. A by having a narrower test with regular rectangular pore frames throughout the test rather than irregular pore frames on earlier chambers and regular pore frames on &64257;nal post-abdominal chambers.

Further remarks: Broctus ruesti Yeh is similar to Broctus selwynensis Pessagno & Whalen in general shape of the test and linear arrangement of pores. These two species differ in the shape of the first segments: B. ruesti is pointed apically whereas B. selwynensis is rounded.

Etymology: This species is named for Dr. D. Ruest, in honor of his contribution to the study of Radiolaria.

Broctus ruesti was named by Yeh (1987). Its type specimen is NMNS (000065) and is a 3D body fossil. Its type locality is Suplee-Izee area, OR-536J, which is in a Pliensbachian marine mudstone/limestone in the Nicely Formation of Oregon.