12 



TH. MORTENSEN, ECHINOIDEA. 



from they cannot be identical with the present species. There must thus, evidently, 

 occur at least two species of Temnopleurus along the West Coast of Australia. 



6. Temnotrema elegans n. sp. 



Pl. IV, Figs. 4- C; Pl. V, Fig. 3. 



This species is closely related to Temnotrema decorum Döderlein (Pleurechinus 

 bothryoides aut.), with which.it agrees especially in the important feature of having 

 a pair of lateral teeth below the endtooth on the blade of the globiferous pedicellariae. 

 Also the structure of the test is so mnch alike that no quite distinct difference 

 between the two species can be pointed out herein. Judging from the material of 

 the two species available (I have only a single specimen of T. decorum, 18 mm h. d., 

 while the largest specimen of the new species is 15 mm h. d.) the grooves are some- 





-■ 



* 



f - 



i 



Fig. 1. Fig. 2. 



Figures 1 — 2. Apical system of Temnotrema decorum (Fig. 1) and Temnotrema elegans (Fig. 2). 



Both figures '*/i. 



what smaller in elegans than in decorum. It also appears that the secondary ambula- 

 cral tubercles are comparatively somewhat larger in decorum, the series remaining 

 quite distinct nearly to the edge of the peristome, while in T. elegans they disappear 

 soon below the ambitus. The triplets of pores form ares, slightly concave outwards 

 as in T. decorum. 



More distinct characters are found in the apical system. It is distinctly elevated 

 above the level of the test, only a very small outer part of the genital and ocular 

 plates being at a level with the upper part of the test, sharply limited against the 

 thickened inner part of these plates. In T. decorum this limit is not nearly so sharp, 

 and the outline of the thickened part is different, as seen by a comparison of the 

 two textfigures 1 — 2. The outer part of these plates is darker coloured than the 

 inner thickened part. The periproct is somewhat smaller in elegans and the anal 

 plates fewer and slightly larger than in T. decorum. The peristome is entirely naked, 



