ECHINOIDEA. I. 77 



between two kinds of tridentate pedicellariæ. The neck is rather short, the stalk of the coramon 

 structure (PI. XIV. Fig. 31). The cover-plate of the triphyllous pedicellariæ is rather well developed, 

 with numerons small holes; the outer part of the blade is not very broad, the edge finely serrate 

 (PI. XII. Fig. 16). 



The .spicules of the tnbe feet on the actinal side are large, generally somewhat curved fenes- 

 trated piates (PL XIV. Fig. 4a); they inclose the foot completely and are not distinctly arranged in 

 longitudinal series. A little sucking disk is found with a rather irregular calcareons rosette (PI. XIV. 

 Fig. 4). Just below the sncking disk the spicules stick, so that this part of the tube foot cannot 

 be contracted, whereas the otlier part is highly contractible, as is comnionly the case in the Echinids; 

 the point with the sncking disk is then seen to be sharply marked off from the other, mucli thicker 

 part of the tube foot. In the contracted jjart the spicules are arranged in such a way as to form an 

 imbrication. The tube feet of the abactinal side have, as usual, no sucking disk, and the spicules are 

 small, irregular, branched calcareous bodies (PI. XIV. Fig. 4 a), arranged in 2—3 longitudinal series. 



The sphæridiæ are as usual placed along the tube feet quite up on the abactinal side, where 

 they are situated at the large tube foot, i — 3 sphæridiæ at each foot. They are rather lengthened 

 (PL XIV. Fig. II). 



Together with tliis specimen a beautiful, small one has been taken, as mentioned above, of a 

 diameter of 27""", which I suppose will have to be referred to the same species, although it differs 

 somewhat from the large specimen with regard to the structure of the test (PI. IV. Figs. 4, 5). The 

 ambulacral areas are somewhat narrower than the interambulacral ones, also on the actinal side. The 

 tube feet are placed in three series, but not very far from each other; they are arranged in arcs of 

 three as in an Echtmis^ which is especially distinctly seen on the abactinal side. The small ambula- 

 cral piates are not distinct, the primary ones are especially regular and straight; this applies also to 

 the interambulacral piates, which are, accordingly, not yet angularly bent as in the adult. The primary 

 spines and tubercles form rather regular series in both areas; in the ambulacral areas there are on 

 the actinal side a couple of especially large ones near the ambitus, much larger than the adjoining 

 ones; in sonie jjlates spines are quite wanting. In the interambulacral areas the}' form a more regular 

 series on either side gradualh- increasing in size towards the ambitus; primary tubercles are found in 

 all the piates, and some have, besides, a few secondary tubercles. On the abactinal side the series of 

 tubercles are very regular in the ambulacral areas where the size is about the same till towards the 

 apical area. The tubercles of the interambulacral areas are more unequal, some being quite small, 

 others very large. The spines, unfortunately, are all broken. The apical area is large, the madre- 

 porite rather distinct. No genital papillæ are as yet developed, nor are the pores as yet formed. 

 The pedicellariæ are as in the large specimen, but as yet no large tridentate pedicellariæ with the blade 

 filled by a thorny net of meshes are found. Of the tube feet on the abactinal side only the innermost 

 one of each are is well developed, the two others are rudimentary as in the large specimen. The 

 spicules of the tube feet of the actinal side are as those of the large specimen, only somewhat smaller 

 and distinctly arranged in series. The sucking disk only slightly developed. In the abactinal tube 

 feet the spicules have only just begun to appear. 



Sperosouia Grimaldii was hitherto only known from the Azores, from c. 600 — 930 fathoms. As 



