256 



THE VOYAGE OF H.M.S. CHALLENGER. 



Oil comparing the species collected by the Challenger in this district, we find that the 

 Challenger traced the existence oi Echinus acutus, Echinus elegans, and Echinus norvegicus 

 to the eastward of Cape Cod, and also of Echinus acutus as far south as Ascension, and 

 of Echinus elegans to Tristan da Cunha ; Cidaris t-nbuloides to Fernando Noronha, and 

 Dorocidaris 2)«2^iU(ita, to St Paul Rocks and Buenos Ap'es. Scdenia varispina was also 

 found as far as Ascension, and the Northern part of Brazil. Echinocyamus j^usiUus 

 Metalia pectoralis and Homolampas fragilis are also found ofi" the latter shores. 



Schizaster fragilis has also been found by the United States Fish Commission iu the 

 Gulf of Maine ; it was found by the Challenger off the Nova Scotia coast, and wth the 

 exception of Pourtcdesia p)hicde no species from the Southern Ocean find then- way north- 

 ward in the Atlantic. There are found on the western side of the Atlantic of the abyssal 

 species Aspidodiadema microtubercidatum, Urechinus naresianus, Cystechinus clypeatus, 

 Aceste hellidifera, and Hemiaster zonatus, while Brissiis damesi is thus far only known 

 from Northern Brazd and the Azores. On the eastern side are found Aceste hellidifera, 

 Hemiaster zonatus, Phormosoma tiranus, Asthenosoma fenestratum, Aspidodiadema 

 tonsuni, Ccdymne relicta, Aerope rostrata, Porocidaris purpurata ; Salenia hastigera, 

 and Scdenia varispina ; Salenia varispina, Brissus damesia, Hemiaster zonatus, 

 Pourtcdesia jeffreysi, Neolampas rostrata, Temncchinus macidatus, and Trigonocidaris 

 cdhida being thus far the only strictly Atlantic species. Spatangus purpureus was 

 found by the Challenger at the Azores and Bermudas, and I have dredged it from the 

 Caribbean Seas, while we have along this district, as might be expected, quite a weU- 

 marked continental fauna agreeing fairly mth the associated littoral fauna in geographical 

 range, but, as has been stated, made up of representative species for the greater part. 



