ECHINOIDKA. I. 



167 



12. Only every otlier interanibnlacral plate above the ambitus 

 with a primary tubercle; the primar\ spines lather short, 



greenish; the form of the test ahnost globular Ecliitms nielo Lamk. 



Only a few interambiilacral piates nearest to the apical 

 area want primary tubercle; the primary spines most fre- 

 qiiently rather long, reddish; the test high or more or less flat Echimis ocutus^) Lamk. 



13. The spicnles branched in the ends, none dnmb-bell-shaped ; 

 the globiferous pedicellariæ with long, muscnlar neck; no 



glands on the stalk. The pores multigeminate Strongyloccntrotiis drobachinisis (Miill.) 



The spicnles of the pedicellariæ dinnb-bell-shaped, those 

 of the tnbe feet branched in the ends; the globiferous 

 pedicellariæ without neck, with glands on the stalk. The 

 pores multigeminate Sphærcchimis granuiaris^) (Lamk.). 



Several results of importance to the study of the geographical distribution will appear from 

 the present researches. A complete representation of these results must, however, be delayed, till the 

 irregular Echinids have been treated. Here I shall only briefl\- mention one feature of greater interest, 

 viz. the resemblance between the arctic-subarctic and the antarctic-subantarctic Echinid-fauna , as this 

 resemblance is chiefl)- based on the regular Echinids. 



Meissner (285) gives a comparison of the Echinid-fauna of the two regions after the state- 

 ments in the literature: one species occurs in both these regions, is bipolar , viz. Echinus norveg icus. 

 The foUowing species represent each other: Cidaris canalictdata and papillata, Echinus magcllanicris 

 and iniliaris, E. margaritaciits and clcgaiis, Strongyloccntrofiis albits and drobachiensis, Schizastcr Phi- 

 lippa a.r\å fragilis. I shall express no opinion with regard to the two .SVÅ/cffjA-r-species , but all the 

 other points of resemblance between the two faunas are quite illusory. I have shown above that 

 Echinus norvegictts is not bipolar. The statement originales from Agassiz ( Challenger> Echinoidea 

 p. 117), but is wrong. The specimens (from st. 308) that have been referred to Ech. norvegicus, are 

 partly Stercchinits iiiagcllanic7is. partly an Echimis-species that has nothing to do with norvegicns; it 

 belongs to the species with primary tubercle on all the ambulacral piates; it is perhaps a new species. 

 — • Cidarisi canaliculata and papillata can in no way be said to correspond to each other, they belong 

 to two different genera, Stcrcocidaris and Dorocidaris; any two other Cidarids might as justly be said 

 to represent each other. Echinus- magcllanicus and n/iliaris, to be sure, are rather .similar with 

 regard to habitus, but as they belong, not only to two different genera, but to two different sub- 



■) With regard to var. medilcyyanea^ Flemingii, antl norvegicus I must refer to the description above (pp. 154—155). 

 ■•] I cannot give the characters of Sphærechinus rosens more particularly, as I have not seen this species; the reader 

 is referred to Ru s s o' s de.scriptioii of it (347). 



