{1194}_Synopsis of the Genera of Tripocyrtida._ ------------------------------------------------------------------------- I. Subfamily Sethopilida. Terminal mouth of the thorax a simple wide opening. -------------------- A. Three radial ribs (or cortinar rods) partly or completely enclosed in the wall of the thorax. No latticed vertical cephalic wings. ------------------------------------------------------------------------- a. Three thoracic { { Feet solid, 534. _Dictyophimus_. ribs prolonged { Cephalis { into three { with a horn. { Feet latticed, 535. _Tripocyrtis_. terminal feet. { { No horn, feet solid, 536. _Sethopilium_. { Thorax { With horn, 537. _Lithomelissa_. { perfectly { b. Three thoracic { latticed. { No horn, 538. _Psilomelissa_. ribs prolonged { into three { Thorax with spongy framework, 539. _Spongomelissa_. lateral wings. { { Thorax with three large { lateral holes between { the three ribs, 540. _Clathrocanium_. c. Three thoracic { ribs completely { Peristome simple, smooth, 541. _Lamprodiscus_. enclosed in the { wall of the { Peristome with a corona of flat thorax { spines, 542. _Lampromitra_. ------------------------------------------------------------------------- B. Three radial ribs enclosed in the wall of the thorax and connected with the cephalic horn by three latticed vertical wings. ------------------------------------------------------------------------- a. Thorax { No frontal horn (four spines), 543. _Callimitra_. completely { latticed { With frontal horn (five { spines), 544. _Clathromitra_. b. Thorax with three large lateral holes between the three ribs. No frontal horn, 545. _Clathrocorys_. ------------------------------------------------------------------------- C. Three radial beams (or cortinar rods) perfectly free, not enclosed in the wall of the thorax. ------------------------------------------------------------------------- Three beams outside the thorax, arising freely from the collar stricture (no cephalic hole), 546. _Eucecryphalus_. Three beams inside the thorax. Cephalis with a large apical hole, 547. _Amphiplecta_. ------------------------------------------------------------------------- D. Three radial terminal feet on the peristome (the three original lateral ribs are lost). ------------------------------------------------------------------------- Feet solid, 548. _Lychnocanium_.