5. Echinothrix calamaris (Pallas). 



PI. III. Figs. :>, 13, 17, 21, 30. l'l. IV. Fig. 7. IM. V. Figs. 3, 11. 

 Ecbinotlirix calaiimris. Acassiz. 1872. Revision of Echini, p. 119, 413. l'l. III a. Kig. 1—2. l'l. XXXV. 

 Fig. 10-15. 



— dcsorii. Aga.ssiz. Ibidem, p. 120, 415. 



Echinothrix Desori. Loiiioi,. 1883. Catalogue rais, des Echinodermcs de Maurice, p. 14. 



— — — 1893. Echinodermes de la Baie dAmboine. p. 3(i2. 



— — KoiiHLKii. 1895. Echinodermes des iles de la Sonde, p. 411. 



— calamaris. Dodkriæin. 1902. Echinoidea von .\niboina u. Thursday Isl. p. 698. Taf. MX,i), 



LXlII,(i. 



— — De Meijere. 1904. Echinoidea d. Siboga-Exped. p. 51. 



For the numerous references to the old literature I must refer to Ac.assiz and for other less 

 important references to the later literature to de Meueke (Op. cit.). 



'«''A 



m 



•I 



Fig. 3. 



This species was not taken by the author in the Gulf of Siam, 

 hul the „Skeat'-Expedilion took a specimen at the East Coast of Redang. 

 Hence it may be mentioned here. 



The structure of the test and the spines is well known from the 

 works cited, so I need not say anything thereof. I shall only give a 

 figure of the curious serrate point of the ambiilacral spines (Fig. 3.); 

 it may also be remarked that in large specimens there are s[)ines on 

 the buccal plates, this feature thus not being exclusive for the genus Cen- 

 trostephanns among Diadematids, as said by Agassiz. 



The pedicellariæ arc quite insufficiently known. Perrieh') has 

 figured a valve of a small tridentale pedicellaria and a triphyllous pedi- 

 cellaria, the figure of the latter (PI. 4. Fig. 3a) being rather coarse, .so that 

 it is somewhat difficult to recognize in it the slender and elegant tri- 

 phyllous pedicellariæ. De Meueke (Op. cil. p. 53) has described the 

 claviform pedicellariæ. The figures 33 — 30, PI. XXIV in „Rev. of Ech." 

 said in the explanation of the plate to be of Ech. calamaris are really 

 Ech. diadema, under which species they are rightly mentioned in the 

 text (p. 416). 



The tridentate pedicellariæ^ occur in two forms. In the one 

 larger form (15 mm., head) (PI. III. Fig. 5, 13, 30) the valves are wide 

 apart, joining only at the end, which is somewhat widened, making a 

 distinct angle with the lower jjart of the edge. The blade is a little 

 The point of Curved, narrow, flat and filled with a coarse meshwork. The edge of 

 an ambula- the outcr part is closely, but irregularly serrate; the lower part may be 



cral spnie of quite smootli or with more or fewer small teeth. The neck is rather 

 Echinothrix , , rr., • ,. , • i i ü • • i • 



short. This lorm , however, varies very much both in size and m 

 calamaris. ? ' j 



(Zeiss. A. A. shape. The part, where the valves join, may be larger (PI. III. Fig. 3t)), 

 Oc. 1.) equalling half the part of the blade, or they may even join throughout 

 ') Rech, sur les pédii ellaires. p. l:i<i. PI. 4. Fig. 3 a— c. 



