Family LVI. Cannobotryida, Haeckel (sensu emendato).
Cannobotryida, Haeckel, 1881, Prodromus, p. 440.
Definition.—Botryodea monothalamia, the shell of which represents a lobate cephalis, without thorax and abdomen.
The family Cannobotryida (retained here with a stricter definition than originally was given in my Prodromus) comprises those Botryodea, in which the whole shell is represented by the cephalis alone, without thorax and abdomen. Since the two latter joints, found in the two following families, are secondary productions, the Cannobotryida must be regarded as the ancestral forms of all Botryodea, in an ontogenetic as well as in a phylogenetic sense.
Two species only of this family have been hitherto known, incompletely described by Ehrenberg as Lithobotrys triloba and Lithobotrys quadriloba. A great number of similar forms are to be found in the Radiolarian ooze of the Central Pacific, but they are very minute, and difficult to examine. We can describe here only twelve species of these, which we arrange in two genera; Botryopera without porous tubes, and Cannobotrys bearing a variable number of porous cylindrical tubes (one to five). The number of lobes of the cephalis is also variable in each genus (one to five or more). If in the future these minute and interesting shells should be better examined, it would be advisable to distinguish a number of genera according to the different number of the porous tubes and of the lobes of the cephalis. The base of the latter is constantly closed by a basal lattice-plate, and usually exhibits two or three pairs of cortinar pores, identical with those of the Semantida.
The phylogenetic origin of the Cannobotryida may be found either in the Zygospyrida or in the Monocyrtida; they differ from these two similar groups in the lobation of the cephalis, which is effected by the development of internal septa and external constrictions.
Synopsis of the Genera of Cannobotryida.
| Cephalis without porous tubes, | 486. Botryopera. |
| Cephalis with a variable number of porous tubes, | 487. Cannobotrys. |
Genus 486. Botryopera,[[104]] n. gen.
Definition.—Cannobotryida without tubes on the cephalis.