lOO ECHINOIDEA. II. 



«Chall. -Ech. p. 185, ou Ilcmiastcr gibbosiis\ only somewhat longer and less widened in the point. The 

 widening is, e.specially in the clavulæ, 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 di.sk, not lobed in the edge. The rosette -piates have been fignred by Loven (On Ponrtalesia. 

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

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

 ones; they are arranged in two longitudinal series. The 6— gth (loth) piates 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 pedicellariæ were hitherto unknown; only Agassiz nientions from H.Mciifzi »afew large, 

 stout-stemnied, globular pedicellariæ, irregnlarly scattered over the abactinal surface of the test v. (^Blake-- 

 Echini. jx 68). I find all the usual forms : globiferons, rostrate, tridentate, ophicephalous and triphyllou.s. 

 The globiferons pedicellariæ (PI. XV. Figs. 47— 48), which occnr both on the abactinal and the actinal 

 side, are rather conspicuous; the head is abont o-5™™, the stalk ca. i"""; no neck. The valves are much 

 cnrved. 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 .^ Talisman*, 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 pedicellariæ (PL 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- 

 rally short, but may 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 

 le.ss .serrate. No neck; the head of the largest specimens seen of this kind was o'S'"™. — The tridentate 

 jiedicellariæ are of two kinds; the one (PI. XV. Figs. 17, 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, tube.shaped. The second form (PI. XV. Fig. 26) is larger (head ca. 0-4"""), the valves 

 join in their outer half, the edge of this jxirt being somewhat irregnlarly serrate. Only one specimen 

 of this kind was seen; perhaps transitional forms may be foimd. — The rostrate pedicellariæ with a 

 large terminal widening may be rather like this second form of tridentate pedicellariæ, and it may 

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

 -— as, npon the whole, the distinction of these two kinds of pedicellariæ is not very sharp. — The 

 ophicephalous pedicellariæ (PI. XV. P'ig. 31) I have found only in the smaller specimens; they are small, 

 shortstalked, without a neck and with the upper end of the stalk cupshaped, as usnally among the 

 Spatangoids. The blade is round, only faintly serrate in the edge; there is uo prolongation from the 

 lowermost of the three arcs. — The triphyllons pedicellariæ have a somewhat elongate blade, rather 



