Two feet grown {Feet simple, 449. _Gamospyris_. together and { uniting to form a {Feet with a series of ring. Apex with a { lateral spines, 450. _Stephanospyris_. horn. ------------------------------------------------------------------------- III. Subfamily Tetraspyrida. Two sagittal and two lateral feet. ------------------------------------------------------------------------- {Apex with one horn, 451. _Tetraspyris_. Feet simple, not branched. { {Apex without a horn, 452. _Tessarospyris_. ------------------------------------------------------------------------- IV. Subfamily Hexaspyrida. Six basal feet. ------------------------------------------------------------------------- Two sagittal, two pectoral,{Apex with one horn, 453. _Hexaspyris_. and two tergal feet. { {Apex with three horns, 454. _Liriospyris_. { {Apex without a horn, 455. _Cantharospyris_. ------------------------------------------------------------------------- V. Subfamily Pentaspyrida. Five basal feet. ------------------------------------------------------------------------- One caudal, two pectoral, {Apex with one horn, 456. _Clathrospyris_. and two tergal feet. { {Apex with three horns, 457. _Ægospyris_. { {Apex without a horn, 458. _Pentaspyris_. ------------------------------------------------------------------------- VI. Subfamily Therospyrida. Four paired lateral feet. (Two pectoral and two tergal.) ------------------------------------------------------------------------- Apex with one horn, 459. _Zygospyris_. Apex with three horns (one apical and two frontal), 460. _Elaphospyris_. Apex with two lateral or frontal horns, 461. _Taurospyris_. Apex without a horn, 462. _Therospyris_. VII. Subfamily Polyspyrida. Numerous (seven to twelve or more) basal feet. ----------- Apex with one horn, 463. _Petalospyris_. Apex with three horns (one apical and two frontal), 464. _Anthospyris_. Apex with numerous horns, 465. _Ceratospyris_. Apex without a horn, 466. _Gorgospyris_. VIII. Subfamily Circospyrida. No basal feet. -------------------------------------------- Apex with one horn, 467. _Circospyris_. Apex without a horn, 468. _Dictyospyris_. {1025}Subfamily 1. TRIPOSPYRIDA, Haeckel, 1881, Prodromus, p. 441.