396 KCHINODERMATA. 



greater or less approximation of the bands of holes, the equality or 

 inequality of the tubercles, &c. * 



The regularity of certain round and depressed Echini is diminished 

 by a wide furrow on one sidef. 



Some of these Echini, where the mouth is opposite to the anus, 

 instead of having a spheriodal form on a circular plane, are trans- 

 versely oval, that is to say, one of their horizontal diameters is greater 

 than the other J. 



They also differ among themselves by the equality or inequality of 

 the spines, and the relative proportions of the tubercles. 



We should distinguish one species — Echinus atratus, L.; En- 

 cyc, 140, 1 — 4 — in which the widened spines, truncated and 

 angular at the extremity, touch each other like stones in a pave- 

 ment. Those of the margin are long and flattened. 



We call all those Echini irregular, in which the anus is not oppo- 

 site to the mouth. It appears that they are merely furnished with 

 short and slender spines, almost like hairs. Of these, some still have 

 the mouth in the middle of the base. 'J'hey may be subdivided ac- 

 cording to the extent of the bands of holes that transmit the feet; 

 sometimes, as in the preceding ones, they extend from the mouth to 

 a point directly opposite, where, after having elapsed the whole shell, 

 they re-unite. 



EcHiNONEus, Phels., Leske., 

 Where we observe the round or oval form of certain regular Echini, 

 the mouth in the middle of the base, and the anus between the mouth 

 and the margin, or near the latter, but underneath §. 



NucLEOLiTEs, Lam., 

 The same characters, with the anus near the margin, but above. 

 The species known are all fossil ||. Others again, 



* Ech. miliaris,, Kl., II, A, B; Encyc, 133, 1, 2;—Ech. hemisphericus, Kl,, II, 

 E ; Encyc, lb., 4 ; — Ech. angulosus, Kl., II, A, B, F; Encyc, lb., 5, 6, 7; — Ech. 

 excamtus, Kl., XLIV, 3, 4; Encyc, lb., 8, 9, very diffeient from Scill., XXII, 2, D, 

 which belongs to the preceding section; — Ech. saxafilis, Kl., V, A, B; Encyc, 

 134,5, 6; Echsca'aiilis, B, Seb., Ill, xiii, 10, is very different, and belongs to 

 the preceding section; — Ech. fetiesfraf us,, KL, IV, A, B; — Ech. suhangularis, Id., 

 Ill, C. D; Encyc, 134, 1, 2 •,—Ech. diadema, Kl., XXXVII, 1 ; Encyc, 133, 10; — 

 Ech. radiatus, Seb., Ill, xiv, 1,2; Encyc. 140, 5, 6 : — Ech. circinnatus, KL., XLV, 

 10 ; — Ech. coronaUs, Kl., VIII, A, B; Encyc, 140, 7, 8; — Ech. asferisans, Kl., 

 VIII, F ; Encyc, 140, 9 ■,—Ech. sardicus, Kl., IX, A, B ; Encyc,, 141, 1,2 \—Ech. 

 flammeits, K1.,X. A; Encyc, l4l, 3; — Ech.variegalus, Kl., X., B, C; Encyc, 141, 

 4, 5 ; — Ech cjranulutus, Kl., XI, F; Encyc, 142, 1, 2 ; — Ech. foreumaticus, Kl., X, 

 D, E, Encyc. 142, 4, 5, &c ; I do not however pretend to answer for all the syno- 

 i.ymes, or to assert that there are no repetitions. 



f Ech. sinuatus, Kl., Vlil, A; Encyc, 142, 7, 8. 



X Ech. lucunter, Kl.. II, E, F; Seb., X, 16, and the species figured in Seb., lb., 

 17 and 8. 



§ Oval species; Echinus cychsfomus, Miill., Zool. Dan., XCI, 5, 6; Encyc, 153, 

 19, 20;— Ech. semilunaris, Seb., Ill, x, 7; Encyc, 153, 21, 22; — Ech. scutiformis, 

 Scill., Corp. Mar., XI, No. ii, fig. 1, 2. 



Round species: E, Encyc, 153, 1, 2; Ech. rfepressiw, Walck., II, E, ii, 6, 7; En- 

 cyc, 152, 7, 8:— Ech. subuculus, Kl., XIV, L— O; Encyc, 153, 14, 17. 



[I Spatunyus. depressus, Leske, ap. Klein, LI, fig. 1,2; Encyc, 157, 5, 6. 



