REPOKT ON THE ECHINOIDEA. 207 



(1 new species), 15 Clypeastridfe (all known species), 2 Nucleolidas (1 new species), 13 

 Pourtalesia3 (12 new species), 6 Ananchytid^ (5 new species), 10 Spatangina (all pre- 

 viously known species), 18 Brissiua (10 new species). 



GEOGRAPHICAL AND BATHYMETEICAL RANGE. 



At the time I published the Revision of the Echini (1872-74) there were enumerated 

 207 species distributed in 89 genera. This was a very material reduction of the number 

 of species formerly recognised, and yet it included a couple of the deep-sea species dredged 

 by the "Porcupine" and all the deep-sea species (13) discovered up to that time by 

 Mr Pourtales. Of the strictly littoral species there were not known at that time more 

 than 192 species and 74 genera. In the general list now given there are 297 species and 

 107 genera enumerated, making in all 90 species and 25 genera added to the former 

 list in spite of the reduction in number by the cancelling of a few nominal species of 

 the older lists ; not more than ten well-characterised species have been added by various 

 writers to the list of the Revision in addition to the species discovered by the deep-sea 

 dredging expeditions. 



This leaves 80 deep-sea species described since those of Mr Pourtales ; of these 49 were 

 discovered by the " Challenger," and 41 by the "Porcupine," "Josephine," and "Blake." Or 

 about one-third of the whole number of known species of Echinoidea have been discovered 

 since the days of deep-sea dredgings ; of these 5 were brought to light by the " Josephine," 

 the same number by the "Porcupine " ; twenty-eight have thus far been described from 

 the Coast Survey Expeditions ("Blake," "Bibb," and "Hassler"), and 49 from the 

 " Challenger." 



One new genus was discovered by the "Porcupine," and one by the "Josephine," nine 

 by the Coast Survey Exj^editions, and 15 by the " Challenger." But in addition to these 

 new genera, 7 genera previously only known from fossils, were added to the present 

 list, either by the "Blake" (3), "Challenger" (2), "Josephine" (1), or "Porcupine" (1). 



The following compendium of our knowledge of the geographical, bathymetrical, and 

 geological range of the recent Echinids will be found convenient for reference in the 

 discussions which foUow. 



The only species which are not included in this list are those of the " Gazelle." A 

 preliminary report of these Echinids has been published by Dr Studer,^ and 1 have in 

 the descriptions of the species of the " Challenger " referred to the species which 1 con- 

 sider as identical or closely allied. The species described by Studer are from compara- 

 tively shallow water, and probably all belong to the Littoral Fauna. 



1 Monatsber. der K. AkaJ. J. W., Berlin, Jidi 1876. 



