REPORT ON THE RADIOLARIA. 1241 



meshes, closing also the basal mouth. (In fig. 5 the greater part of the web is taken off U> 

 demonstrate the large holes of the thorax). Only two feet are visible. 



Dimensions. — Cephalis 004 long, 005 broad ; thorax 009 long, 0-12 broad. 



HabUai. — Central Pacific, Station 274, surface. 



2. Clathrohjchnus penplectus, n. sp. (PI. 64, fig. 6). 



Cephalis subspherical, with subregular, circular pores and a pyramidal horn of the same length. 

 Length of the two joints = 1 -.2, breadth =1:3. Thorax with three large elliptical holes between 

 the three pyramidal, divergent feet, which are connected at the distal end by a broad band of net- 

 work, composed of five to ten rows of polygonal pores. The entire pyramidal shell is enveloped by 

 a very delicate web, which on the sides is composed of subregular, square meshes, and on the closed 

 mouth of polygonal meshes. (In fig. 6 only a part of the web is represented.) 



Dimensions. — 004 long, 005 broad ; thorax 0-08 long, 0-14 broad. 



Hdbitat. — Central Pacific, Station 271, surface. 



Family LXIII. A n t h o c y r t i d a, n. fam. 



Sethyphormida et Sethophxnida, Haeckel, 1881, Prodiomus, p. 432, -133. 



Definition. — D i c y r t i d a multiradiata. (C y r t o i d e a with a two-jointed 

 shell, divided by a transverse constriction into cephalis and thorax, and bearing- 

 numerous — four to nine or more — radial apophyses.) 



The family A n t h o c y r t i d a, composed of the Sethophormida and Sethophsenida of 

 my Prodromus, comprises those C y r t o i d e a in which the shell is two-jointed and 

 bears numerous radial apophyses. The two subfamilies differ in the shape of the 

 mouth, which in the Sethophormida is a simple, wide opening ; in tlie Sethophsenida 

 closed by a lattice-plate. 



Numerous fossd and living forms of Anthocyrtida were described formerly by 

 Ehrenberg in his genera Carpocanium and Anthocyrtis. These, however, represent 

 only a small part of the whole family, which exhibits a great variety in the composition 

 of the lattice-work and in the number of radial beams. The number of species here 

 described amounts to one hundred and forty, and these are disposed in fourteen genera 

 (twelve Sethophormida and two Sethophaenida). 



The Sethophormida may be again divided into two different groups or tribes, the 

 Setliamjihorida and Carpocanida ; in the former the thorax bears numerous radial 

 ribs, enclosed in its wall ; in the latter these ribs have disappeared, and only a corona 

 of terminal feet is developed around the mouth. The shell of the former is usually 

 pyramidal, with a widely open mouth ; of the latter ovate, with a constricted mouth. 

 The mouth of the thorax becomes perfectly closed in the Sethophsenida. 



(ZOOL. CHALL. EXP. — PART XL. — 1886.) Rr 156 



