ECHNIOIDEA. II. m 



The rostrate pedicellariæ (PI. XIV. Figs. ir, 15,43) li^ve the valve.s very little widened in the 

 point; thev 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 (PI. XIV. Fig. 43). This kind of pedicellariæ is 

 especiallv developed ronnd the mouth and in the anterior ambnlacrum; also on the anal area they 

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

 less conspicuous than the globiferous ones; the length of the head up to ca. 0-5"'"'. The neck is short, 

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



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

 oped, the valves var\ing from simply leafshaped to almost tubnlar, but all intermediate forms occur, 

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

 tliose 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 may be 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 reprcsented in Fig.s. 18, 46, 50. PI. XIV and in Doderlein's 

 Fig. 2. b, f. PI. Li. Another form has the narrow lower part of the blade more distincth' set off from 

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

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

 or more or less recalling the rostrate pedicellariæ (PI. XIV. P'igs. 3, 7) and perhaps they ought really 

 to be reckoued to that t\pe; this, however, cannot be decided and is of no importance. — Large tri- 

 dentate pedicellariæ with almost tubular 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 pedicellariæ 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. 



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

 3—6'"'" 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 

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



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

 area; thej' do not present features of specific valne, and are almost spherical, smooth or grooved. 

 — The spicules (PI. XIV. P'ig. 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 piates. Loven (Pourtalesia. PI. X. Fig. 100) figures the rosette-plates as reaching only 

 halfway out in the lobes; I find them generalh- 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 10""" length. The 'Ingolf >-Expedition has taken (especially at Station 28) several small specimen.s, 

 the \oungest 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 a™™ upward.s, a development which j^roves of 110 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 faet endocyclic, closel)- joining the two large anterior genital piates, while the 



