34 



by Agassiz in „Rev. ofEch." PI. XXIV fig. 37). The ophiccphalous pedicellariæ (PI. III. 

 Fig. 4) are essentially as in C. longispiniis. Agassiz (Rev. of Ech. PI. XXIV. 37') figures 

 a valve of an ophiccphalous pedicellaria without the usual arc below the basal part, 

 and from this fact he concludes (Op. cit. p. 664) that „the buccal pedicellariæ of the 

 Diadematidæ dilTer from those of the Echinidæ in having a solid base". This cannot 

 be held as a general rule; the base of the valves is only partly solid. In each ophicc- 

 phalous pedicellaria two of the valves have the usual arc, only the third may have a 

 solid base, but this even does not seem to be always the case. — The globiferous pedi- 

 cellariæ (Pi. IV. Pig. 19) are like those of C. longispinus, only with more elongated 

 blade and larger teeth at the point; there are not always glands on the stalk, those 

 without glands being larger than the other ones. There seem to be glands on the 

 outside of the valves. — Though C. Rodgersii looks very different from C. longi- 

 spinus, there can be no doubt that they are nearly related, and they are rightly 

 refen-ed to one genus. 



Through the kindness of Prof. Döderlein I have had occasion to examine 

 the pedicellariæ and spicules of Cænopedina {Hemipedina} mirabilis. Meantime de 

 Meijere has given an excellent description with figures of his C. (//. ) indica (Siboga- 

 Echinoidea. p. 65), and as the two species agree rather closely as regards pedicellariæ 

 and spicules, I need only say a little of this very interesting form. — The spicules 

 are like those of C. indica, and are arranged in two series as in that species. I have 

 seen a single bihamate spicule in the gills. The globiferous and ophicephalous 

 pedicellariæ (PI. IV. Fig. 3, 5— 6) present some small dilTerences, as will be seen by 

 comparing the figures given here with de Mei.iere's figures from C. (//.) indica 

 (P\. XVI. Fig. 237 — 4Ü). The triphyllous pedicellariæ are quite like those of indica. 

 Tridentate pedicellariæ are not mentioned by de Meijere for C. indica; in C. mimbilis 

 I have found a few ones. They are small, simply leafshaped (PI. III. Fig. 12) with- 

 out meshwork in the bottom; the edge is a little sinuate, slightly and irregularly 

 serrate. The valves apparently join in a little more than half their length; the neck is 

 short. Possibly also a second form of tridentate pedicellariæ is found, with narrow, 

 elongated blades, strongly serrate in the edge; ])ut I dare not assert this positively. 

 The stalk of the pedicellariæ is irregularly fenestrated. 



The genera Aspidodiadema and Dermatodiadema have likewise been carefully 

 treated by de Meijere; I may, however, give some additional remarks, especially 

 on the Atlantic species, which are as yet insufficiently known. 



Aspidodiadema tonsum. (This species is the first named in the Preliminary 

 Report on the „Challenger '-Echinoidea, and is thus the type species of the genus). 

 The spicules are arranged in two longitudinal series; Ihey have been figured by de 

 Meijere (PI. XIII. 182j. The tridentate pedicellariæ (PI. V. Fig. 6) are elongate 

 (c. 1 mm. — head) and slender; the valves join in almost their whole length; figures 

 are given of them by de Meijere (PI. XIII. 178 — 80). The neck is well developed, the 

 stalk a single, thick, smooth rod. Also Agassiz has given a tolerable figure of a valve 



