94 SVEN LOVÉX, ON TIIE ECHINOIDEA DESCRIBED BY LINN^US. 



of the one half, «, are parallel, or verv uearly so, to tlie cor- 

 responding series of the other half, b, while the tAvo fourth 

 series of both halves are biit slightly converging upwards. 

 Transversely the protuberanecs are disposed in rows slightly 

 risino- towards the sutiire, and alternating with those of the 

 other half. The connecting ridges, vertical and transverse, 

 form everyw^here meshes, and on the knöts as in the inter- 

 stices are seen very numerous tubercles, large and flat with 

 miuute mamelons, bearing long and powerful pedicellariae. 



This tendency in the opistromal protuberances towards 

 a vertically parallel disposition, strikingly at variance with 

 the convergence of the series of spinigerous tubercles, is not 

 entirely löst in Coelopleurns, though less developed in the C. 

 Maillardi Mich. In a specimen of Coelopleurns floridanus 

 Al. Ag.^), for which I am likewise indebted to its first de- 

 scriber, the bright red epistroma on each of the five costals 

 rises into a high protuberance from which rows of low elon- 

 o-ated granules are diao-onallv directed towards five other emi- 

 nent protuberances, one on each radial. On the ambulacra 

 the epistroma, påle and faintly pustulated, covers the upper 

 part of the disk and the zon?e. On the sides of the interradia 

 it is red, and alono- the middle of each half forms a straight 

 briglitly coloured vertical ridge, bordered outwardly by an im- 

 pressed line, while on the middle of the disk, devoid of tu- 

 bercles and contrasting by its whitish colouring, it is nearly 

 smooth, only crossed obliquely by slightly elevated broad 

 bands and narrow rows of minute nodules. The middle verti- 

 cal area thus marked is but slightly contracting upwards, and 

 less so in the young, as it will appear from Al. Agassiz' fi- 

 gures, the ridges on its flanks having, as it were, an early 

 tendency to become parallel like the vertical rows of protu- 

 berances in Podocidaris. These broad vertical areas, slightly 

 or not narrowing upwards, bordered on each side by a ridge 

 of contiguous or detached nodules, often accompanied by an 

 impressed line, are very conspicuous in the tertiary species 

 described b y Cotteau-) and by Duncan and Släden^). 



') Blake Echinoidea, p. 2.3, PL VII, VIII. 



^) CcBlopleurus Delbosi Desor, Ann. Se. Géol. XV, 2, No 2, p. 4, t. 

 1, fig. 15 20. — C. Tournoueri Cotteau, Act. Soc. Lin. Bordeaux, XXVII, 

 p. 248, t. 12, fig. 1—5. — C. Rousseli Cotteau, Bull. Soc. Zool., XI, p. 

 712, t. 24, tig. 6—11. — C. Arnaudi Cotteau, Ann. Se. Géol., XV, sub 

 C. Delbosi, Ecb. nouv., I, t. 14, fig. 6—10. 



') C. eques Val., Duncan et Släden, Foss. Echin. Sind, IV, p. 251, 

 t. 39, fig. 3—8. — C. Pratti d'Arch., Dunc. et Slad. ib. p. 254, t. 39, fig. 



