REPORT ON THE RADIOLARIA. 1395 



the same length; both covered with numerous small dimples and spinules. Thorax campanulate • 

 abdomen inversely conical ; both with regular, circular pores. Thorax with nine thin curved ribs, 

 which in the upper half of the abdomen arise as nine large feet, which are strongly compressed and 

 curved (with the convexity outwards) ; their distal ends form nine ovate spinulate cones, and lie in 

 the same horizontal plane as the basal apex of the abdomen. 



Dimensions. — Length of the three joints, a 0'04, b 0'09, c O'lG ; breadth, « 0-05, b 012, c 01, 



Habitat. — Indian Ocean, Madagascar (Ealjbe), surface. 



2. TJieopliaina nonaria, n. sp. 



Shell thorny, ovate, with two slight strictures. Length of the three joints =1:4:5, breadth 

 = 1:5:4. Cephalis subspherical, with a conical horn of half the length. Thorax subspherical, 

 with regular, circular pores and conical spines. Abdomen ovate, smooth, with irregular, roundish 

 pores. In the upper half of the thorax descend nine straight, little divergent ribs, which in the 

 lower half become free, and represent nine slender, conical wings ; their distal ends do not reach the 

 horizontal plane in which the basal end of the abdomen lies. 



Dimensions. — Length of the three joints, a O'OS, b 012, c 015; breadth, a 0'03, b 014, c 012. 



Habitat. — South of Australia, Station 160, surface. 



Family LXVII. Theocyrtida, n. fam. 



Theocorida et Theocapsida, Haeckel, 1881, Prodromus, pp. 434, 436. 



Definition. — T ricyrtida eradiata. Cyrtoidea with a three -jointed shell, 

 divided by two transverse constrictions into cephaUs, thorax, and abdomen, without 

 radial apophj^ses. 



The famUy Theocyrtida, composed of the Theocorida and Theocapsida of my 

 Prodromus, comprises those Cyrtoidea in which the lattice-shell is three-jointed, 

 and bears no external radial apophyses. The two subfamilies differ in the shape of the 

 terminal mouth, which in the Theocorida is a simple wide opening, in the Theocapsida 

 closed by a lattice-plate. The phylogenetic origin of the Theocyrtida may be found 

 either in the Podocyrtida or in the Sethocyrtida ; they may have been derived from the 

 former by reduction and loss of the three primary apophyses, or from the latter by 

 development of an abdomen. 



The number of species in this group is very large, and many belong to the most 

 common and widely distributed Cyrtoidea. A great number of living and fossil 

 species have already been described by Ehrenberg, the majority being disposed in his 

 genera Lithocampe and Eucyrtidium. 



The number of genera, however, is comparatively small, and their distinction 

 difficult, since the form of the shell presents no striking differences. 



