ECHINOIDEA 347 



2. Echinosigra IVIrtsn. 



Test more or less conspicuously narrowed in the anterior part, 

 again widened in the front, giving the appearance of a head and 

 neck. A distinct dorsal and ventral keel, the latter continuing 

 into a distinct anal snout, surrounded by a fasciole. Periproct 

 situated above the anal snout. The posterior paired ambulacra 

 not disconnected, the postero -lateral interambulacra not uniting 

 on the ventral side. Labrum, which is large and distinctly seen 

 from without, is widely separated from the second plate of the 

 posterior interambulacrum through the neighbouring ambulacra 

 joining in the ventral mid-line behind the labrum (Fig. 204, 2). 

 Apical system disconnected, at the frontal edge of the test. 



The two only knoTVTi species of this genus probably both occur 

 in the British seas. 



Key to the species of Echinosigra. 

 Neck moderately long . . . . 1. Ech. phiale (W. Th.) 



„ very long and slender ... 2. Ech. paradoxa Mrtsn. 



1. Echinosigra phiale (WyY. Thomson). (Fig. 208.) 



(Syn. Pourtalesia phiale Wyv. Thomson.) 



Test not very much narrowed in the anterior end, forming 

 only a short neck ; middle part of body not conspicuously 

 swollen. Labrum and adjoining ambulacral plates only moder- 

 ately long. The enlarged second plates of these ambulacra, which 

 join in the mid-ventral line behind the labrum, with a short 

 dividing line in the anterior edge. Anal snout not bent upwards. 

 Periproct scarcely sunk. Spines short, scattered, mostly bifid 

 at the point. Globiferous pedicellarise unknown. Tridentate 

 pedicellariae (Fig. 209, 1) very characteristic, with the valves ending 

 in a long point ; the ophicephalous mainly as those of Pourtalesia, 

 only with fewer serrations ; the rostrate (Fig. 209, 3) with the blade 



from P. Wandeli. In the opinion of the present author the original 

 description and figures of Pourtalesia miranda (in Revision of Echini, 

 p. 345, PI. XVIII.) make the identity of the two forms improbable. The 

 fact that specimens from the West Indies, later on identified by Agassiz as 

 P. miranda, are identical with P. Wandeli, only prove that also the latter 

 species occurs in the West Indies. The type specimen of P. miranda 

 having been lost, the question of the possible identity of the two forms 

 cannot be definitely solved at present. The West Indian specimens 

 referred to P. Wandeli were taken in depths of only 435-1035 m. 



