ECHNIOIDEA. II. m 



The rostrate pedicellaricc (PI. XIV. F'ig.s. ir, 15,43) 'i^ive the valves ver\- little widened in the 

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

 with only 4 small teeth. Not seldom thc\- are 4-valved (PI. XIV. Fig. 43). This kind of pedicellaricc is 

 especialh' developed ronnd the mouth and in the anterior ambulacrum; also on the anal area they 

 often occur, but generally onh- small ones. Upon the whole these pedicellaricC are smalk'r and much 

 less conspicuous than the globiferous ones; the length of the head nj) to ca. o-5™"'. The neck is short, 

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



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

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

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

 those with large leafshaj^ed valves, narrowed in the lower part, widened towards the point, where 

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

 with onh' 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. PI. XIV and in Doderlein's 

 F'ig. 2. b, f. PI. L). Another form has the narrow lower part of the blade more distinct!}' set off from 

 the outer, widened part, and the point of the blade more or less distincth- bent inwards (PI. XIV. 

 Fig. 25). Quite small specimens may be simply leafshaped (PI. XIV. F'ig. 20, and DTiderlein's Fig. 2. c), 

 or more or less recalling the rostrate pedicellaricC (PI. XIV. F'igs. 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 pedicellarite with almost tnbnlar blade (PI. XIV. Fig. 37) I have found only in a large specimen 

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

 almost exclusively on the actinal 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. 



Ophicephalons pedicellarite (PI. XIV. P'ig. 39) I have found onh' on quite young specimens of 

 3—6™™ length. They are of the usual Spatangoid type, without neck. The blade is broadh' triangular, 

 continuing almost down to the articular surface, the apophysis being .short and broad. The tri])hyllous 

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



The splueridice 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 (PI. 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 lobe.s. 



In the <: Blake »-Echini (p. 74) Professor AgJassiz describes >-oung specimens of Sch. fragilis of 

 6 and 10""" length. The «Ingolf -Expedition has taken (especially at Station 28) several small specimens, 

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

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

 interest. (PI. XIII). 



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

 abactinal side; it is, in fact endocjclic, closely joining the two large anterior genital plates, while the 



