Gate irregularly quadrangular or nearly semicircular. Ring quadrangular, edgeless, with four unequal sides; ventral rod more curved and with longer sides than the dorsal rod. From the four edges arise four strong, irregularly branched spines, about as long as the diameter of the gate, {949}with curved branches; the ventral and basal spines larger than the dorsal and apical spines. Similar to _Lithocircus quadricornis_ (Pl. 81, fig. 9), but less branched, and with a striking difference between the shorter dorsal and the longer ventral rod. _Dimensions._--Diameter of the gate 0.04 to 0.06; length of the spines 0.05 to 0.07. _Habitat._--North Pacific, Station 256, depth 2950 fathoms. 2. _Dendrocircus dodecarrhiza_, n. sp. Gate obliquely ovate. Ring irregularly quadrangular, with three prominent edges. From the latter arise at the four corners twelve divergent, irregularly branched spines (three in each corner), about as long as the radius of the gate, with curved branches; the three basal spines larger than the nine others. _Dimensions._--Diameter of the gate 0.08 to 0.1; length of the spines 0.04 to 0.06. _Habitat._--Indian Ocean (Maldive Islands), surface (Haeckel). 3. _Dendrocircus dodecancistra_, n. sp. (Pl. 81, fig. 11). Gate obliquely ovate or nearly elliptical. Ring irregularly ovate, with three distorted edges and six pairs of branched spines. The two ventral pairs are much more distant than the two dorsal pairs, the ventral rod being longer and more curved than the dorsal rod. All twelve spines are of nearly equal size, are more or less curved, about as long as the diameter of the gate, and each bears six to twelve irregular short branches at the end. _Dimensions._--Diameter of the gate 0.07 to 0.08; length of the spines 0.05 to 0.08. _Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. 4. _Dendrocircus arborescens_, n. sp. (Pl. 81, fig. 10). Gate irregularly roundish or nearly circular. Ring of the same form, with slight edges and six pairs of elegant arborescent spines (one apical, two dorsal, two ventral, and one basal pair); the three latter somewhat larger than the three former. Each tree is larger than the ring, in the basal half simple, in the distal half forked, each fork-branch with numerous dichotomous terminal branches. _Dimensions._--Diameter of the gate 0.06 to 0.08; length of the spines 0.12 to 0.15. _Habitat._--Central Pacific, Stations 266 to 274, surface. 5. _Dendrocircus elegans_, n. sp. (Pl. 81, fig. 13). Gate irregularly ovate. Ring thick, ovate, with three denticulate edges and six bunches of stout, branched and spinulate, curved spines. The four ventral spines are more distant than the four dorsal, the ventral rod being more curved than the dorsal. The latter bears above the two apical spines. The two basal spines are much larger, deeply forked; their four fork-branches may be compared to the four basal feet of _Stephanium_.