Ernst Haeckel

“ Definition.—Cœlodendrida without external lattice-mantle, with branched radial tubes, the hollow branches of which are free and never connected by anastomoses.
The genus Cœlodendrum is the first described form not only of the family Cœlodendrida, but of all Phæoconchia or bivalved Phæodaria; it is also the most common form of this group, and represented by ten different species, some of which are cosmopolitan, very common, and widely distributed. ”

“ I have already pointed out the difficulty of distinguishing between Lithocampe and Eucyrtidium. The general form of the shell exhibits a continuous series of transformations, from a flat, conical, or nearly discoidal form, through cylindrical to ovate, or spindle-shaped shells, the wide open terminal mouth becoming more or less constricted, and finally (in the Stichocapsida) closed. The absence or presence of an apical horn may further serve for the distinction of genera. ”

“ The lattice-work of the shell exhibits in the Cyrtoidea an extraordinary variety, similar to that of the Sphæroidea; it serves in the first place for the distinction of species. The three first joints of the shell are often distinguished by the different character of the lattice-work. The cephalis has usually very small and simple pores. The lattice-work of the thorax is often characterised by radial structures. The pores of the abdomen are usually very numerous and regular. The numerous joints in the annulated abdomen of the Stichocyrtida commonly exhibit little variety. ”

“ Definition.—Sagosphærida with a delicate spherical shell, the thin wall of which is composed of a simple lattice-plate and covered with numerous pyramidal elevations; each pyramid bears on its top one or more radial spines, and has an internal axial rod in its radial axis.
The genus Sagenoscena differs from the preceding closely allied Sagoscena in the possession of an internal radial axial rod, which arises in the centre of the base of each pyramid, and is prolonged usually over its apex into a free, radial, apical spine. ”

“ The characteristic structure of their central capsule, as true Tripylea, was afterwards, in 1879, described more accurately by Richard Hertwig (Organism. d. Radiol., p. 90, Taf. x. figs. 2, 8, 14) . The rich collection of the Challenger has demonstrated that the Aulosphærida belong to the most common and most widely distributed Phæodaria; many of them are distinguished by the admirable elegance and astonishing regularity of their large and delicate shell. ”

“ The "cephalis or capitulum" (the "Köpfchen" of the German authors) is therefore the most important part of the skeleton in all Cyrtellaria, or in all Nassellaria possessing a complete lattice-shell. In the Plectellaria, however, or in those Nassellaria which do not possess a complete fenestrated shell, the "cephalis" is either imperfect or totally wanting. The cephalis surrounds the enclosed central capsule on all sides in the form of an ovate or subspherical lattice-shell, and is separated from it only by the jelly-like calymma. ”

“ The large hollow tubes which arise from the galea of all Cœlographida, are very variable in number, size and shape, but are always richly branched and symmetrically arranged in the dorsal and the ventral valve of the shell. They exhibit an important difference in the two subfamilies of the group; in the Cœlotholida all the branches, and also the thin terminal ramules, are free, without any junction; in the Cœloplegmida, however, they communicate by frequent anastomoses, and the connected terminal ramules form on the surface of the calymma an outer lattice-mantle of very delicate network. ”

“ The hollow articulate feet, or the large radial apophyses of the peristome, are the most remarkable organs of the Medusettida, and occur in the same form in no other family of Radiolaria. Their number is variable from three to twelve or more, and is here employed for the distinction of genera, as it is rather constant; the most frequent number is four (Medusetta) or six (Gazelletta) . The feet are usually cylindrical, much longer than the shell, and more or less curved; more rarely they are straight or slightly compressed. ”

“ In a few groups only, especially in the Cannobelida (Dictyocha, Mesocena, &c.) , and in a part of the Castanellida and Concharida, the substance of the skeleton seems to be of pure silica, as in the Nassellaria and Spumellaria; these flinty skeletons, therefore, may be also found fossil. In the majority of Phæodaria, however, the skeleton does not consist of pure silica, but of an organic silicate; it becomes more or less intensely stained by carmine, and browned or blacked by fire; in many cases it even becomes completely burned and destroyed by the prolonged action of heat. ”

“ The Cœlographida, finally, have a phæodium of the most remarkable shape, since in their bivalved shell a peculiar reserve store or magazine of phæodella, which we call the "phæocapsa" is developed for it (Pl. 126-128, g.t.m.) . The bivalved shell has in these most perfect Phæodaria a structure similar to that in the Cœlodendrida; but they differ from the latter in the stronger development, and greater differentiation of the two apical galeæ, and the large hollow tubes arising from them. ”

“ Definition.—Phæodaria with a bivalved lattice-shell, composed of two hemispherical valves, a dorsal and a ventral. A conical cupola or a helmet-shaped galea arises on the apical pole of each valve, therefore on the opposite poles of the sagittal axis. The cavity of the galea communicates with the sagittal rhinocanna, a peculiar nasal tube, which rests upon the valve, and is connected with the galea by a simple or double frenulum; its opening being directed towards the proboscis. Three or more branched hollow radial tubes arise from each valve, and are symmetrically disposed. ”

“ The structure of this proboscis or peristome is usually the same as in the diatomaceous shell-wall; but sometimes its lattice-work assumes a different shape.
The opening of the mouth itself is rarely circular, usually it is elliptical or even lanceolate, often triangular. Sometimes two prominent opposite lips may be distinguished as right and left, when the fissure of the mouth is prolonged in a sagittal or longitudinal direction; as upper and lower, when it is prolonged in a frontal or transverse direction. The upper or dorsal lip is always more developed than the lower or ventral ”

“ The two poles of the frontal (lateral or transverse) axis are equal and are determined by the two parapylæ of the capsule, and the corresponding points of the shell-fissure between both valves. Usually the main-axis is the longest, the frontal axis the shortest, and between both the sagittal axis.
In regard to the three dimensive planes which are determined by these three axes, perpendicular to one another, they are rarely of nearly equal size (as in some subspherical species) , usually the sagittal plane (separating the right and left halves of the body) is the largest ”

“ The Podocyrtida represent one of the largest groups of Cyrtoidea, very rich in numerous species, which are partly very common and widely distributed. A large number of living and fossil species has already been described and figured by Ehrenberg, (1872, 1879, loc. cit.) . These mainly belong to his genera Podocyrtis, Pterocanium, Rhopalocanium, Lithornithium, &c., and many of them are very characteristic and common forms, in which the triradial structure of the three-jointed shell is visible at first view. ”

“ This large number of species may be easily increased by accurate researches on the great masses of Lithocampida, which are found in the Radiolarian ooze of the Challenger, and as fossils in Barbados. The variety in the number, size, and proportion of the shell-joints and of the lattice-pores is very great, and permits us to distinguish a far greater number of species than are here described. Many species are cosmopolitan, and belong to the most common forms of Radiolaria. ”

“ Definition.—Stephoidea with two crossed vertical rings, perpendicular one to the other (the primary sagittal and the secondary frontal ring) . Usually their common base bears a horizontal basal ring, but a mitral ring (or a horizontal ring at the apex) is never developed.
The family Coronida comprises those Stephoidea in which the primary sagittal ring (of the Stephanida and Semantida) becomes crossed by a second vertical ring, the lateral or frontal ring. ”

“ As the ascending rods alternate regularly with the corner-spines of the basal ring, we may call the latter perradial, the former interradial. Ehrenberg has distinguished in his genus Dictyocha not less than fifty species, thirty-five living and twenty-five fossil (ten species both living and fossil) . The greater part of these cannot be retained, as they are only slight varieties or abnormalities of single pieces of the skeleton, such as very frequently occur associated with the common regular forms in one and the same individual. ”

“ Spines of very different size and shape, three-sided prismatic, verticillate. The apical spine (or horn) with ten to twelve verticils, is one and a half times as long as the three basal spines (or feet) , which bear six to eight verticils only; each verticil with three branches which by communicating ramules form a loose irregular wickerwork. Similar to Pteroscenium pinnatum, Pl. 53, figs. 14-16, but without a regular lattice-shell. A short basal central rod separates two equal (pectoral) spines from two unequal spines, the larger of the latter is the apical, the shorter the caudal spine. ”