ECHINOIDEA. II. 95 



tailed. I have found globiferous, rostrate, tridentate and triphyllous pedicellariæ, whereas ophicephalons 

 ones were not met with. The globiferous pedicellariæ have a large space in the blade continuing almost 

 down to the articular surface; evidently it includes a gland, as is the case in the globiferous pedi- 

 cellariæ of the Cidarids. The terminal opening is small, transversely elongate, with one tooth on each 

 side; the basal part is rather wide, with rounded, smooth edges. (PI. XV. Fig. 14). The Fig. 45, PL XLIV 

 of the Chall. -Ech. evidentl)- represents a valve of this kind; that the figure is not sufficiently cor- 

 rect will be seen by a comijarison with the figure given here. I have never seen them with the edge 

 of the basal part serrate. The rostrate pedicellariæ (PI. XV. Fig. 32) have rather short and robust val ves, 

 a little widened in the point, which is serrate in theusualway; the apophysis generally a little serrate. 

 They may, however, also have more elongate and slender valves, with the terminal part somewhat 

 larger. (PL XV. Fig. 15). The stalk has a distinct milled ring below. Very small pedicellariæ (PL XV. 

 Fig. 36) which may perhaps also be termed rostrate are found in rather great numbers inside the 

 fasciole (on the lateral ambulacra) and in the fasciole itself, among the clavnlæ. The tridentate pedi- 

 cellariæ are very richly developed, being represented by no less than three distinct form.s. The simplest 

 form has elongate, narrow, simply leafshaped valves, which join in their whole length. The edge is 

 finely serrate. In the specimen from the «Albatross> this form is more elongate and narrow; the edges 

 in the lower part are bent a little inwards and smooth (PL XV. Fig. 51). The second form of tridentate 

 pedicellariæ (PL XV. Fig. 22) has the edge of the blade very coarsely dentate; the blade otherwise is 

 leafshaped. The third form (PL XV. Fig. 25) is rather like the more slender rostrate pedicellariæ, the 

 blade being narrow with a widened point; but this widened part is not sharply set off from the narrow 

 part, bending gently inwards. The two latter forms have only been found in the specimen from the 

 fiAlbatross». The stalk of all three forms has the upper end thickened, the lower end provided with a 

 distinct cmilled ring. The ueck may be well developed or quite short. — The triphyllous pedicellariæ 

 are like very small and simple tridentate pedicellariæ. 



The spicules (PL XV. Fig. 41) are simple rods, a little spinous (generally only at the ends), not 

 so numerous as those of Acropsis. The piates of the rosette are elongate and narrow, flat, the edges 

 not curved as in those of Aeropsis (PL XV. Figs. 10, 39). — The peculiar clubshaped spines found in 

 the anterior ambulacrum are ' interesting as showing a possible transition from normal to more special- 

 ised spines, which may in part perform the functions of pedicellariæ > (« Chall »-Ech. p. 196). They are 

 certainly interesting, but that they have anything to do with the functions of pedicellariæ there is 

 nothing at all to prove — it seems, indeed, very improbable that they can perform functions like those 

 performed by the pedicellariæ with their movable valves. It might seem more appropriate to compare 

 them with the sphæridiæ which are undoubtedly only specialised and transformed spines. 



Professor Rathbun (332. p. 89) suggests the possibility of another species of this genus occur- 

 ring in the Atlantic, on account of a small specimen which 'differs considerably from the larger speci- 

 mens -, withoirt giving, however, anything more detailed about these differences. Perhaps the existence 

 in the Atlantic of a species distinct from A. bcllidifcra would account for the differences between the 

 figures of the pedicellariæ given by Agassiz and by me. In faet I am unable to find in the sjDecimens 

 examined b}- me pedicellariæ corresponding passably to the Figures 27 and 28, PL XLII, Fig. 25. 

 PL XLIII and Fig. 46. PL XLIV of the • ChalL»-Ech. The fig. 28. PL XLII evidently represents the 



