jQQ ECHINOIDEA. II. 



< Cliall. -Ecli. p. 185, on Hcmiastcr gibbnsus\ only somewhat loncjer and less widened in the point. The 

 widening is, especially in the clavnke, unequally developed, being largest on the posterior side of 



the spine. 



The tube-feet of the anterior ambulacrum within the fasciole are large and prominent, with a 

 large disk, not lobed in the edge. The rosette-plates have been figured by Loven (On Pourtalesia. 

 PI. X. 92); they sometimes bifurcate in the outer part. The spicules are simple, more or less spinulose 

 rods (PI. XV. Fig. 38), mostly very numerous in the abactinal tube-feet, less numerous in the actinal 

 ones; they are arranged in two longitudinal series. The 6— 9th (lOth) plates of the median series of 

 the bivial ambulacra bear large tube-feet like those at the mouth, corresponding to the large tube- 

 feet within the subanal fasciole of Brissopsis etc. 



The pedicellarise were hitherto unknown; only A gas si z mentions from Il.Mcntzi <• a few large, 

 stout-stemmed, globular pedicellarise, irregularly scattered over the abactinal surface of the test . ( Blake»- 

 Echini. p. 68). I find all the usual forms: globiferous, rostrate, tridentate, ophicephalous and tnphyllous. 

 The globiferous pedicellaria; (PI. XV. Figs. 47— 48), which occur both on the abactinal and the actinal 

 side, are rather conspicuous; the head is about o-s""™, the stalk ca. i"""; no neck. The valves are much 

 curved. The blade is quite closed, tubeshaped, ending in a transverse-oval opening, whose outer edge 

 is generally provided with 6 teeth, the inner edge being generally smooth. The basal part is rather 

 wide, with smooth edges. In a specimen from the Talismans, examined in the Paris Museum, I find 

 also the inner edge of the terminal opening provided with teeth and the edge of the basal part more 

 or less serrate (PI. XV. Fig. 24). The stalk is simple without thickenings or free projecting rods. The 

 rostrate pedicellarice (PI. XV. Figs. 9, 16, 18) have rather straight valves, curved only at the outer end. 

 The blade is narrow, open, with a terminal widening, differing to some degree in extent; it is gene- 

 rallv short, but nuiy take as much as the outer half of the blade. The edge of the widened part is 

 finely serrate, the edge of the lower part smooth; in larger specimens there may be some cross-beams 

 between the edges in the lower part of the blade. The edge of the basal part is generally more or 

 less serrate. No neck; the head of the largest specimens seen of this kind was o-5""". — The tridentate 

 pedicellaria; are of two kinds; the one (PI. XV. Fig.s. 1 7, 30, 45) is very small (head ca. 0-2'"'"), with a 

 well developed neck. The blade is simply leafshaped, a little narrowing below. The edge is smooth 

 in the lower part, serrate in the outer part, the serrations increasing in size towards the end of the 

 blade and generally directed outwards, which gives the valves a rather characteristic appearance. The 

 stalk is delicate, tubeshaped. The second form (PI. XV. Ing. 26) is larger (head ca. o-4"""), the valves 

 join in their outer half, the edge of this j)art being somewhat irregularly serrate. Onl\- one specimen 

 (if lliis kind was .seen; perhajjs transitional forms may be found. — The rostrate pedicellariie with a 

 large terminal widening may be rather like lliis second form of tridentate i)edicellarite, and it may 

 not always be possible to detennine whether such a pedicellaria is to be termed rostrate or tridentate 

 - as, upon the whole, the distinction of these two kinds of pedicellarise is not very sharj). The 

 ophicephalous pedicellaritc (PI. X\'. Ing. 31) I have found only in the smaller specimens; they are small, 

 sliortstalked, without a neck and with the upper end of the stalk cupshaped, as usually among the 

 Spatangoids. The blade is round, only faintly serrate in the edge; there is no prolongation from the 

 lowermost of the three arcs. — The triphyllous pedicellaria: have a somewhat elongate blade, rather 



