ECHINOIDEA. II. ,j 



and not cnp-shaped at tlie upper end; the neck is well developed. The blade is coarsely dentate along 

 the whole edge; the lower jjart of the blade is very narrow, forniing a small tube. The basal part is 

 not distinctly developed, the articular surface is broad and well developed. Sonie larger fonns, very 

 similar to these, niight also be termed triphyllons pedicellariæ, but from analogy with the Ech.grandi- 

 porus described Ijelow, in which species there can be no donljt that these are tridentate pedicellariæ, 

 the larger ones niay also be termed tridentate in piisilliis. (PI. XII. Fig. 23I. The blade is more elong- 

 ated than in tht- triphyllons; the edge is serrate, the serrations on the point being the larger, often 

 considerably larger than in the one fignred; the basal part as in the triphvllons. Size ca. o-o8— 0-09'"'". 



The buccal membrane does not contain any piates or spicnles; the same holds good for the 

 internal organ.s. The genital organs are mnch branched and interlaced, but apparentlv not anastomo.s- 

 ing, forming a broad ring. The axial organ shows some distinct swellings. The madreporic plate has 

 on the inside a deep and large impre.ssion for the axial organ and the ampuUa. 



The largest specimen of this .species seen by me is 15'"™ in lengtli. The size 9 lines (20"""! 

 given in Zoologia Danica (loc. cit.) seems hardly correct. It is very \ariable as regards the shape of 

 the test. This has cansed older anthors | L. Agassiz, Forbes) to distinguish a nnmber of species; 

 based almost exclusiveh on differences in the shape of the test, viz. among the recent forms: E. pit- 

 silliis. aiigitlijsHs and famifiinis. besides a nnmber of fossil species from the Tertiaries. Philippi (op. 

 cit.) has first pointed out that these differences are unreliable for specific characters, since all the dif- 

 ferent forms ma\- be fonnd among specimens from the same locaUt>-. Philippi and all the later 

 anthors after him (except Forbes) therefore regard all the recent forms from the European seas as 

 one species including also several of the fos.sil species . I quite agree with this, and might further 

 add as synon\mous the E. luspidiihis Forb. and E. oviforviis Forb., both from the Crag, examples of 

 the .same shape as these occurring likewi.se among the recent specimen.s. — Forbes further disting- 

 uishes no less than six different varieties of EcJi. pusillus, all of which, he agrees, • may be taken in 

 one locality at the present day . It is evident that all these forms cannot rank as varieties , thev 

 represent merely individual variations in the shape of the test. — Perhaps the specimens from the 

 Færoe Islands ma> rank as a distinct variet\-. On comparing them with specimens from the Kattegat 

 and the :\Iediterranean I find that the nnmber of pores is upon the whole a little smaller in the former 

 (comp. the tables given below, p. 34); but it is no constant feature, specimens from the Færoe Islands 

 occnrring with as large a nnmber of pores as is generall\ found in the specimens from the Kattegat. The 

 shape of the test is upon the whole more elongated than in the specimens from the Kattegat; also, the 

 primary spines are generalh- somewhat less serrate than those of the typical form, sometimes even quite 

 smooth ones nia>- be fonnd. — The specimens from the Limfjord may also be distingni.shed as a local 

 form, remarkable for the close tubercnlation. — The Mediterranean form I am iniable to distinguish as a 

 separate \ariet\-: the}- closeh- agree with the specimens from the Kattegat. The same holds good for 

 the specimens from the Azores. 



This species was taken b\ the Ingolf« at St. 86 (Brede Bugt, Iceland, 7 dead tests). At the 

 Westmanoer, I)r. A. C. Johansen has taken 4 dead tests (30 fathoms); in the Zoological Museum is 

 fonnd further an old dead test from Reykiavik. These are, so far as I know, the onl\- specimens of 

 Echinocyamus pnsillus known from Iceland; it thus seems that the species does not li\'e there now. 



