Botryodea (= Botrida vel Botryida), Haeckel, 1881, Prodromus, p. 439.
Definition.—Nassellaria with a complete lattice-shell, exhibiting constantly a lobate and multilocular cephalis, with three to five or more separated lobes, and two to three or more constrictions.
The suborder Botryodea differs from the other Cyrtellaria in the multilocular and lobate shape of the cephalis, which is composed of at least three or four, often five or six, and sometimes even a greater number of lobes, which are separated by constrictions and partly also by internal septa. This characteristic shape is found neither in the Spyroidea (with bilocular cephalis) nor in the Cyrtoidea (with simple cephalis). The affinities of the former group to the two latter form a very complicated problem, which is not yet solved; the morphology of the Botryodea is the most difficult part in the system of Nassellaria, and what we can here give, are incomplete and unsatisfactory beginnings only.
Up to the year 1860 only a single genus of the Botryodea was known, Lithobotrys, one of the oldest genera of "Polycystina," and described by Ehrenberg in 1844 (Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 74). He gave the following definition:—"Loricæ siliceæ articuli in adulto non in seriem, sed in uvæ brevis formam, id est in loculos plus minus discretos nonnullos contiguos dispositi. Proxime ad Lithocampem accedit." In his first System (1847) Lithobotrys is placed with Lithocampe among his family Lithochytrina. Afterwards (1860) Ehrenberg added two new genera, under the names Botryocampe and Botryocyrtis and figured some species of these incompletely in his last works (1872, 1875).
In my Monograph I founded for these three genera the separate subfamily of Polycyrtida, added as a fourth genus Spyridobotrys, and gave to the group the following definition (1862, loc. cit., p. 341):—"Lattice-shell divided by two or more annular strictures, partly longitudinally, partly transversely, into three or more unequal chambers, which are placed in different planes and have a different relation to the poles of the shell-axis."
The new and remarkable forms of Botryodea, which I subsequently found in the Challenger collection, demonstrated that the Botryodea differ from the other Cyrtellaria (the Cyrtoidea as well as the Spyroidea) in a far higher degree than I formerly had supposed. A synopsis of the figures in Pl. [96] will give sufficient evidence of this view. Therefore in my Prodromus (1881, p. 439) I completely separated the Botryodea (or Botrida) from the other suborders of Cyrtellaria (Spyrida and Cyrtida).
Bütschli gave, in 1882, in his paper on the Cyrtida (loc. cit.) a very accurate description of Lithobotrys geminata, and pointed out its close affinity to Lithocorythium and Lithomelissa, and the importance of an oblique septum separating the cephalis into a smaller anterior and a larger posterior lobe. His views on the Botryodea (as a subordinate group of the Cyrtoidea) are however incomplete, since the peculiar forms, described in the following pages, were unknown to him.
According to the wide morphological divergence of the different Botryodea, and the numerous peculiar forms developed from it, we here divide the whole group into three families and ten genera, with fifty-five species. These form, however, only a small part of the large and varied mass of closely related forms which are found in the rich collections of the Challenger. The great difficulty of researches on their intimate structure, and the great amount of time required for it, prevented me from giving a more complete and exact description than the one here given. The observation of the small shells from all the different sides is a difficult task, requiring years of work, and its satisfactory explanation would be possible only by means of numerous figures.
The three families of Botryodea, here described, correspond to the three first groups of Cyrtoidea. The first family, Cannobotryida, corresponds to the Monocyrtida clausa and to the Zygospyrida; their shell consists of a cephalis only, without subsequent joints. The second family, Lithobotryida, corresponds to the Dicyrtida and Phormospyrida; their shell is composed of a cephalis and a thorax, both joints being separated by a transverse cortinar septum and a collar stricture. The third family, Pylobotryida, has a three-jointed shell, like the Tricyrtida, with cephalis, thorax and abdomen.
The cephalis is the most characteristic part of the shell of the Botryodea and its lobulate and multilocular shape separates them from the Spyroidea and Cyrtoidea. It represents the whole shell in the Cannobotryida, and in the young state of the two other families, which afterwards develop a thorax (Lithobotryida) and an abdomen (Pylobotryida). The typical lobulation of the cephalis is probably originally caused by internal septa; and these may be originated by branches of the internal columella, which corresponds either to the central ascending columella of the Plectoidea or to the excentric ascending dorsal rod of the sagittal ring of the Stephoidea. But afterwards, when the original septa disappear and are lost by reduction, only the external constrictions remain to indicate the limits of the single lobes.