103 



(and spicules) unfortunately are unknown. The validity of this genus can scarcely 

 be doubted; but it seems certain, in any case, that it is very nearly related to Holo- 

 pneastes, with which genus it agrees in the character of the ambulacra, as opposed 

 to all other Temnopleurids (except Salmacis dussumieri). 



Amblypneustes formosus Val. To the description in „Rev. of Ech." p. 479 

 the following remarks may be added. The globiferous pedicellariæ (PI. VI. Fig. 37. 

 PI. VII. Fig. 4) are small, with an unpaired lateral tooth (which may, however, be 

 more or less rudimentary); the basal corners not produced. The ophicephalous 

 pedicellariæ (PI. VI. Fig. 9) have short and broad valves; the Iripliyllous pedicellariæ 

 (PI. Vll. Fig. 13) have the blade rather elongate and narrow. Tridentate pedicellariæ 

 I have not seen. — The spicules (bihamate) are rather numerous in the tube feet. 

 The buccal membrane contains the usual ring of plates in the oral 

 edge, otherwise it is naked — excepting the buccal plates, of course — 

 but with numerous bihamate spicules. The gills contain some few of 

 the common irregular plates and numerous bihamate spicules. The 

 primary spines (Fig. 9) are almost equally thick in their whole length, 

 ending quite abruptly in a little central peak surrounded by small 

 thorns at its base; sometimes the central thorn is not seen. The point 

 is not swollen (PI. II. Fig. 27). The secondary spines are more or less 

 swollen at the point; they may have a distinct central thorn like the pri- 

 mary ones, or the point may be covered by very small thorns, without 

 a larger central one. 



Amblypneustes ovum (Lamk.) is most nearly related to A. formosus, 

 with which it agrees in having slender primary spines, not thickened 

 at the point. The secondary spines are thickened at the point, without 

 a central thorn. The globiferous pedicellariæ are like those of A. formosus. 

 The ophicephalous pedicellariæ are very variable in shape, the valves 

 being short and broad like that figured for A. formosus or very elongate 

 (PI. VII. Fig. 50), and between these extremes all transitional forms are 

 found. Tridentate pedicellariæ occur in this species; they are rather 

 small (c. 08 mm., head); the valves are simply leafshaped with rather 

 much meshwork in the bottom (PI. VII. Fig. 11), the edge is very finely sen-ate, 

 the outer part sinuate: they join in their whole length. They have an arc below 

 the basal part like the ophicephalous ones and can, indeed, hardly be distinguished 

 from the larger ophicephalous pedicellariæ. The triphyllous pedicellariæ are like 

 those of A. formosus. Spicules are scarce in the tubefeet, numerous in the buccal 

 membrane and at the base of the spines. 



This species, when preserved with the spines, can only be confounded with 

 A. formosus, from which species, however, it seems very well distinguished, espe- 

 cially by its large ophicephalous pedicellariæ. The base of the spines is dark 

 green in A. ovum, pink in A. formosus; but this is no constant feature, as they may 



i 



Fig. 9. Pri- 

 mary spine 

 of Ambly- 

 pneustes for- 

 mosus {Ob}. 0. 

 Oc. 0|. 



