100 



larger than in specimens of M. zigzag of a corresponding size. The globiferous pedi- 

 cellariæ (PI. VI. Fig. 24. PI. VII. Fig. 38) have no lateral teeth, but as they occur in 

 M. zigzag both with and without an unpaired lateral tooth, it may perhaps be the case 

 here also. The other pedicellariæ are like those of M. zigzag. The secondary spines 

 are much widened at the point and without a distinct central thorn; the primary 

 spines are like those of M. zigzag, but they are very faintly red coloured. No 

 plates in the buccal membrane except the ring at the inner edge and the buccal 

 plates. — The characters pointed out here are certainly not very marked, but the 

 different coloration of the test and spines makes this form look so different from 

 M. zigzag with its dark coloured naked spaces that it must certainly be separated 

 from that species. Perhaps it ought only to be regarded as a variety of M. zigzag; 

 but from the material at hand I must regard it as a distinct species, for which I 

 propose the name Microcyphus elegaiis n. sp. I have seen one more specimen of this 

 species in the British Museum, from the same locality; it was named Amblypneustes 

 ovum (comp, below). The two specimens measure 12-5 mm. in diameter, one US, 

 the other 105 mm. in height. 



At least one more species of Microcyphus exists. A specimen named Micro- 

 cyphus zigzag, from ..Challenger" St. 162 (Bass Strait, 40 fathoms) proves to be 

 quite different from both M. zigzag and elegans and must certainly be made the 

 type of a new species. (As regards the specimens from St. 161, Port Philip, the 

 red banded spines in one of them show it to belong to the same species as the 

 example from St. 162. My notes upon the rest of them are, however, insufficient 

 to settle their position). The test is high as in the two other species, but it 

 presents the very interesting feature of being elongate, the longitudinal axis 

 passing through the ocular plate to the right of the madreporic plate, as seen 

 from above. The short diameter is 128 mm , the long diameter 148 mm. 

 (height 12 mm.), the elongation being thus very distinct. Now, of course, this 

 cannot be concluded with certainty from the one specimen examined to be a 

 constant character of this species; it may possibly be an abnormity. But the 

 specimen otherwise looks quite normal , and it seems probable that this is really 

 a specific character, and one of great interest as the only known example of 

 obliquity of test among the Temnopleuridœ. The naked median spaces are very 

 large, especially the interambulacral ones, comprising almost the inner half of the 

 plates. The tuberculation is much more sparse than in M. zigzag (specimens of equal 

 size being compared); the interambulacral plates bear inside the primary tubercle 

 (at the ambitus) only one secondary tubercle and two or three miliary ones, whereas 

 in M. zigzag there are two (in large specimens three) large secondary tubercles 

 inside the primary one, all together forming a distinct horizontal series. Close 

 above the primary tubercle, a little to the outside of it, there is another large 

 tubercle, almost as large as the primary one; otherwise only quite small tubercles 

 are found outside the primary one. In M. zigzag a corresponding tubercle can be 



