ECHINOIDEA. II. 



185 



Of these species the following are kiiown from tliis region alone: Dorocidaris mida, Rotula 

 Augusfi, Rtimphii, Echinolampas Heilet (the Ecfi. Blanchardi Cotteau is probably onh- a synonym of 

 this species), Schizastcr Edzvardsi, Rhabdobrissiis JulUcni and Mctalia africana; whilst Trctocidaris spi- 

 nosa is known ouly from St. Helena. 



From the Mediterraneau region have probably immigrated: Arbacia fustulosa, Parcchinus micro- 

 tubcrcutatus, Echinus melo and Sphærechimis granularis, from the East American region: Cidaris tri- 

 buloides, Diadcma antillarum, Tripneustes esculentus, Eckinometra lucuntcr, Clypeastcr subdepressns 

 and Meoma ventricosa. The two species Genocidaris macitlafa and Brissus ttnicolor, as stated above, 

 occnr; both in the Mediterranean and East American region. It is worth noticing that the species 

 Cidaris trtbuloides, Tripneustes escnlciitus, Echinometra bicunter, Clypeaster stibdepressus and Mcovia 

 ventricosa are not known from the Mediterranean region. Judging from the cnrrents they (viz. the 

 larvæ) must have passed through the latter region; it is then probably the temperature which is not 

 hig-h enougli here to snit them. 



The East American littoral region comprises the whole, very extensive tract from the mouth 

 of La Plata in the South to Cape Hatteras in the North. Certainly many of the species of this region 

 do not proceed so far towards North or South, but it is scarcely possible to distinguish more than 

 one region here. Its centre is the West-Indies; from here the species extend more or less in both 

 directions, the North American and Brazilian Coast thus having upon the whole a considerably poorer 

 Echinoid-Fauna than the West Indies, without species peculiar to them (except Paracentrotus Gaimardi 

 which is hitherto known only from the Coast of Brazil). 



This region, together with the East American deep-sea region, is by far the richest of all the 

 Atlantic regions and among the richest of the world. No less than 48 species are known from the 

 East American littoral region against 24 species from the Mediterranean, 23 from the West African 

 tropical, and 20 from the European boreal region. The following species are known from the East 

 American littoral reofion: 



Dororidaris papillata 



— abyssicola 



Cidaris affinis 



— tribuloides 

 Tretocidaris Bartletti 

 Aspidodiadema Jacobyi 

 Diadema antillarum 

 Arbacia punctulata 



— pustulosa 

 Coelopleurus floridanus 

 Salenia Pattersoni 

 Trieonocidaris albida 



Genocidaris maculata 

 Echinus gracilis 

 Paracentrotus Gaimardi 

 Psammechinus variegatus 

 Tripneustes esculentus 

 Echinometra lucunter 



— viridis 



Clypeaster latissimus 



— Ravenellii 



— strbdepressus 

 Echinanthus rosaceus 

 Mellita sexforis 



Mellita testudinata 

 Encope marginata 

 — Michelini 

 Echinoneus semilunaris 

 Echinolampas depressa 

 Conolampas Sigsbei 

 Rhyncopygus caribbæarum 

 Palæotropus Josephinæ 

 Palæopneustes cristatus 



— hystrix 



Linopneustes longispinus 

 Palæobrissus Hilgardi 



sefiiihinaris As long, however, as we kuow abnost nothing of the littoral fauna of St. Helena aud the West Coast of Africa 

 South of Congo, we canuot deny the possibiht}- of the occurrence of these species at Ascensiou ; the streams of the Southern 

 Atlantic at least would easily account for their occurrence there, if they were only found off South Africa. But only Cidaris 

 meiiilaria has been recorded from there, and only from older collectious (Rev. of Ech.). 



The Ingolf-Itxpedition. IV. 2. 24 



