ECHNIOIDRA. II. [x] 



The rostrate pedicellariae (PL XIV. Figs, ir, 15,43) have the valves very little widened in the 

 point; they generally end in 6 small teeth; sometimes they are even narrowed in the point ending 

 with only 4 small teeth. Not seldom they are 4-valved (PL XIV. Fig.43). This kind of pedicellariae is 

 especially developed round the mouth and in the anterior ambulacrum; also on the anal area they 

 often occur, but generally only small ones. Upon the whole these pedicellariae are smaller and much 

 less conspicuous than the globiferous ones; the length of the head up to ca.o-5 mm . The neck is short, 

 especially in the larger ones; the stalk is thick and compact. 



The txidentate pedicellariae (PI. XIV. Figs. 3, 7, 18, 20, 25, 37, 46, 50) are uncommonly richly devel- 

 oped, the valves varying from simply leafshaped to almost tubular, but all intermediate forms occur, 

 so that separate forms of them cannot be distinguished. As the more typical form I must regard 

 those with large leafshaped valves, narrowed in the lower part, widened towards the point, where 

 usually some coarse serrations are found; the edge of the lower, narrowed part maybe almost smooth, 

 with only a few large teeth or more closely serrate. There may be a more or less developed meshwork 

 in the bottom of the blade. (This form is represented in Figs. 18, 46, 50. PL XIV and in Doderlein's 

 Fig. 2. b, f. PL L). Another form has the narrow lower part of the blade more distinctly set off from 

 the outer, widened part, and the point of the blade more or less distinctly bent inwards (PL XIV. 

 Fig. 25). Quite small specimens may be simply leafshaped (PL XIV Fig. 20, and Doderlein's Fig. 2. c), 

 or more or less recalling the rostrate pedicellariae (PL XIV Figs. 3, 7) and perhaps they ought really 

 to be reckoned to that type; this, however, cannot be decided and is of no importance. — Large tri- 

 dentate pedicellariae with almost tubular blade (PL XIV Fig. 37) I have found only in a large specimen 

 from the Faroe Islands — perhaps it is an abnormal form. The large tridentate pedicellariae are found 

 almost exclusively on the actiual side, round the peristome and along the ambulacra. They have a 

 well developed neck; the stalk is rather compact, with a more or less distinct milled- ring below. 



Ophicephalous pedicellariae (PL XIV. Fig. 39) I have found only on quite young specimens of 

 3 — 6 mm length. They are of the usual Spatangoid type, without neck. The blade is broadly triangular, 

 continuing almost down to the articular surface, the apophysis being short and broad. The triphyllous 

 pedicellariae (PL XIV. Fig. 31) are of the usual form, with finely serrate edge. 



The spheeridice continue, as is usually the case, along the posterior ambulacra to the anal 

 area; they do not present features of specific value, and are almost spherical, smooth or grooved. 

 — The spicules (PL XIV Fig. 13. a. b) are irregular, spinous rods; in the large tube-feet of the anterior 

 ambulacrum they are more complicated, their protuberances being larger and partly uniting so as to 

 form fenestrate plates. Loven (Pourtalesia. PI. X. Fig. 100) figures the rosette-plates as reaching only 

 halfway out in the lobes; I find them generally reaching almost to the point of the lobes. 



In the Blake -Echini (p. 74) Professor Ag'assiz describes young specimens of Sch. fragilis of 

 6 and io mm length. The Ingolf -Expedition has taken (especially at Station 28) several small specimens, 

 the youngest of which are only 2 mm in length. I am thus able to give a rather full account of the 

 development of this species from a size of 2 mm upwards, a development which proves of no small 

 interest. (Pl.XIII). 



In specimens of 2 mm length (Pl.XIII. Figs. 2, 4) the anal system is almost in the middle of the 

 abactinal side; it is, in fact endocyclic, close!}' joining the two large anterior genital plates, while the 



