33 



Fig. 2); Ihey :iic' t'ound on the buccal plates and on the actinal side of the test, 

 the latter ones generally a little larger, as observed by Koehler, but otherwise not 

 differing in structure. 



The globifcrous pedicellariæ (Globiferæ Hamann) are found only on the test; 

 there are glands on the stalk; the head is very small, and may even be totally wanting 

 (torn off?). No neck; the upper end of the stalk is widened, but not cupshaped. 

 The blade (PI. IV. Fig. 11) is narrow, provided with 4—6 large teeth in the outer 

 end; often one of the teeth has a median position, but it is not larger than the other 

 ones, and there is no canal on its upper side, in accordance with the fact that no 

 poison gland is found on the valve. — It may be disputable whether these pedi- 

 cellariæ are true globiferous pedicellariæ or only somewhat transformed ophicephalous 

 ones. They remind one very much of the ophicephalous (claviform) pedicellariæ with 

 large stalk glands in Aspidodiadema, but in these the valves are of a true ophice- 

 phalous structure. On the other hand they must certainly be taken to be homo- 

 logous to the undoubted globiferous pedicellariæ of Cœnopedina and Stomopnemtes. 

 Evidently we mu.st conclude, that they are a sort of globiferous pedicellariæ, deve- 

 loped from the ophicephalous ones. It may be disputed whether the globiferous pedi- 

 cellariæ of fîc/iiniViœ etc. are really homologous to these forms; but it seems not unrea- 

 sonable. Of course they cannot be derived from such specialized forms as those of 

 Cœnopedina, but between the globiferous pedicellariæ of Centrnstepluinns, especially 

 the forms with a median tooth, and those of Hypsiecbinus and Parecbimis the 

 ditTerence is not so very great. In Cenlr. Rodgersii there seem to be glands on the 

 valves of the globiferous pedicellariæ; if that be really so (my material is not suffi- 

 cient for stating it defmitely), there can scarcely be any doubt that this suggestion 

 of the origin of the globiferous pedicellariæ in Echinidce, Toxopneustidœ and Echi- 

 nometridce is correct. 



The triphyllous pedicellariæ are rather different from those of the other 

 Diadematids. The blade is elongated and Hat, the edge is quite smooth (comp. 

 PI. IV. Fig. 22 — of C. Rodgersii). They remind one very much of those in Stomopneustes. 

 The stalk of the ])edicellariæ is irregularly perforate. The sphæridiæ are elongate, 

 pearshaped and smooth. 



Centrostephanus eoronatus I have not seen; from the description given by 

 Verrill it appears to be very nearly related to C. longispinus, but this cannot be 

 affirmed definitely, before its pedicellariæ and spicules have been examined. 



Centrosteplumns Rodgersii. The spicules are as in C. longispinus, only more scarce 

 in number. The pedicellariæ are of the same four kinds as in that species. The triden- 

 tate pedicellariæ are rather .short, only c. 1 mm. (head): the neck is well developed. 

 The valves (PI. V. Fig. 34) are curved, wide apart, joining only at the point. The 

 blade is narrow, almost flat, filled with meshwork; the edge is straight, with some 

 few thorns, at the outer end sinuate, a little (irregularly) serrate. (A not very good 

 figure of a valve of a tridentate (large-headed, long-stemmed) pedicellaria is given 



D. K. D. Vidensk, Selsk. Skr., 7. Række, niiturvidensk. og uuitheni. Afd. 1. 1. 5 



