REPORT ON THE RADIOLARTA. 1709 



Genus 718. Tuscarusa,^ n. gen. 



Definition. — Tuscarorida witli four radial aboral feet and a variable number of 

 cii'coral teeth. 



The genus Tuscarusa differs from the preceding closely allied Tuscarora in the 

 ■possession of four radial feet instead of three. The mouth of the single observed 

 species is a narrow sagittal fissure, and armed with two opposite teeth (a dorsal and a 

 ventral, as in the subgenus Tuscaretta). The four lateral feet form a cross, and lie 

 opposite in pairs, in two diagonals of the square, which is bisected by the sagittal mouth. 



1. Tuscarusa medusa, n. sp. (PI. 100, figs. 7, 7a). 



Shell ovate, with four crossed lateral feet iii the upper third, and with two opposite teeth around 

 the mouth. The four feet are opposite in pairs in two diameters of the shell, perpendicular one to 

 another, and arise between the upper and middle third of the shell; they are thin, cylindrical, spinidate, 

 arcuate, and ascend to the height of the mouth diverging upwards; then they are curved downwards 

 in a large arc. They He in the diagonals of the square, which is halved by the narrow and long 

 fissure of the mouth. This hes in the original sagittal plane, and from its two corners arise the two 

 opposite teeth (a dorsal and a ventral), diverging upwards, cylindrical and shghtly curved. The 

 base of each foot is pierced by four pedal pores, of each tooth by two dental pores. 



Dimensions. — Length of the shell 1"2, breadth 1"0. 



EaJntat. — North Pacific, Station 253, depth 3125 fathoms. 



Genus 719. Tuscaridium,^ n. gen. 



Definition. — T uscarorida without radial aboral feet, but with a terminal axial 

 caudal foot, and a variable number of circoral teeth. 



The genus Tuscaridium, comprising two closely allied species, differs from the two 

 preceding genera of Tuscarorida in the absence of lateral radial feet, which are repre- 

 sented by a single large caudal spine placed in the main axis of the shell, at its aboral 

 pole. The shell is therefore spindle-shaped, and not ovate or subspherical, as in the 

 two other genera. It reaches in the two observed species a length of more than 

 3 mm. 



1. Tuscaridium cygneum, Haeckel. 



Tuscarora cygnea, Jolm Murray, 1879, m Utteris, Narr. ChaU. Exp., vol. i. p. 226, pi. A, fig. 20. 



Shell spindle-shaped, twice as long as broad (in the transverse section circular), equally tapering 

 towards both poles of the main axis. The aboral pole bears a thin, cylindrical, straight, caudal 

 1 Tuscarusa, derivation from Tiucarora. ^ Tuscaridium, derivation from Tuscarora. 



