^ ECHINOIDEA. II. 



Suborder Amphisternata. 



Fam. Spatangidae. 



It may be expressly stated that by including here in the family) Spatangidcc all the genera 

 mentioned in the following, \\z. Acropsis, Hnniastcr, Schizastcr. Spatangiis, Echinocardiiiui and Bris- 

 sopsis, besides some few others, as Accsfe, Pcriaster which I have taken the opportunit\- to discuss, I 

 do not mean to maintain that all these genera do realh' belong to one and the same faniih'. It is only 

 a provisional arrangement; so long as I have not studied more carefully all the recent genera of 

 Amphisternous Spatangoids, or at least so nian>- of them as are available for me, I do not want to 

 o-ive mv view of their classification. I hope to be able to do so in Part II of the Siam-Kchiuoidea. 



Aeropsis nom. nov. 



The name A rropr l)y which Wyv. Thomson designated the curious Spatangoid dcscril)ed by 

 him in The Atlantic I. !>. 381 was preoccupied and thus cannot be kept for the Spatangoid. It was 

 first used by Leach, though only as a Manuscript name, Aerope bidrns, for a crab of the genus 

 Macrophf halm lis Latr. {Macr.parvimaiins Latr.).' Later on, in i860, it was employed by Albcrs for a 

 pulmonate Gastropod of the I'am. Helicoidea [Aerope caffra; South Africa) ^ It is thus beyond doubt 

 that the Spatangoid named Ai'rnpe in 1877 must have another name. I therefore propose the name 

 Acropsis. which recalls the old familiar name so much that this change of name can scarcch- give 

 much trouble. 



25. Aeropsis rostrata (Wyv. Thomson). 



rl. V. Kigs. 8—10, 15, 20, 22. PI. XV. Figs. 1—2, 5, 8, 13, 19—21, 29, 37, 40, 43, 52. 



Synonym: Ai'ropr rostrata Wyv. Thomson. 



Literature: A. M. Norman: Crustacea, Tunicata, Pol)zoa, Echinodcrmata etc. Uiology of the 

 «Valorous» Cruise 1875. Proc. Royal Soc. 25. 1876. p. 211. — Wyv. Thomson: The Atlantic. I. p. 381. 

 Fig.99. — A. Agassiz: Challenger :-Echinoidea. jx 192. PI. XXXIII. p-ig.s. 6 — 13, XXXIII. a. 8—12, 

 XXXIX. 23, XLI. 7— 8. (Nou.: PI. XXXIIl. i -5.) — Verrill: Results of the Explorations made by the 

 Steamer 'Albatross > off the Northern Coast of U. S. in 1883. (426). p. 539. 



In his description of this species Professor Agassiz points out that his specimens differ con- 

 siderably in outline, as is also very well .seen in the figures given on PI. XXXIIl of the < Challenger >- 

 Ecliinoidea. Nevertheless he does not regard them as different species, and in his recent work <The 

 Panamic Deep-Sea Echini > (p. 194) it is maintained that the differences in outline of the specimen(s) 

 figured on the PI. XXXIIl of the - Cliallengers-Echiuoidea are all coni])atil)le with differences due to 



' Li.sl of speciiiieiis of Crustacea in the British Museum. 1847. p. 37. 

 ' Tryoii: Structural and systeuialic Conchology. 18S4. III. p. 18. 



