JO TH. MORTENSEN, (Schwed. Südpolar-Exp. 



are deepened or not. the main character upon which Philippi distinguished his 

 two sspecies» cavernosus and australis, is only a sexual difference. The rela- 

 tive size of the petals differs conspicuously: the posterior petals are as long as 

 or even a little longer than the anterior ones in Agassizii, somewhat shorter in 

 cavernosus, much shorter in Pliilippii. The frontal ambulacrum is flush with the 

 test in Agassizii, deepened in the other species. A. Philippii has only the an- 

 terior paired petals deepened in the female, while the other species have both the 

 anterior and the posterior petals deepened. The number of genital pores cannot, 

 on the other hand, be used as a certain specific character, two or three pores oc- 

 curring equally frequent!)- in A. Philippii {\\\\\c\\ species was distinguished by LOVEN 

 mainl)- by the supposed character of having onl}' two genital pores); also in typical 

 A. cavernosus two genital pores may occur. (PuiLlPPl says, in his paper »Über die 

 chilenischen Seeigel»: Teh kenne jetzt noch eine Art, bei welcher auf der Hnken 

 Seite gar kein Eierstock liegt»; probably this will turn out to be an individual ab- 

 normality of one of the known species.) — The position of the apical system is gen- 

 erally central in all the species, but in some specimens of cavernosus it is distinctly 

 posterior, without any other characters distinguishing these specimens from the ty- 

 pical form; they can certainly not even be made a separate variety, all transitional 

 forms occurring. Other specimens differ from the typical cavernosus in the unusual 

 height of the test; but here likewise transitional forms occur. 



After all I think \\'e may distinguish with certainty the following species of the 

 genus Abaius: cavernosus (Phil.) (with the synonyms australis Phil. and gallego- 

 sensis De LoktoL), Agassiaii (Pfeffer). Philippii LOVËN and cordatus (Verrill). 

 As for A. elongatus (Koehler) I am much inclined to think that it will prove to 

 be identical with A. As;assizii. ^ 



Abatus cavernosus (Phil.). 



PI. IX. PI. X. Figs. 2, 4. 6-S, 10—13. PI- XVII, Fig. 9. PI. -Win, Figs. 3—4. PI. XIX, Fig;. zS— 30, 



32— 33. 35—39, 41—43- 45-46- 50—51. 



Tripyltis cavernosus Philippi. 1845. Beschreibung einiger neuen Echinodermen. Arch. f. N.iturgesch. XI. 



I. p. 345. T.-if. XI. Fig. 2. 



— ■« australis — Ibidem, p. 347. Taf. XI. Fig. 3. 



Brissopsis cavernosus L. AgasSIZ & Desor. 1S47. Catalogue raisonne des Échinides. Ann. Sc. nat. 3 ser. 



VIII. p. 15. 



— australis — — Ibidem. 



Tripyliis (Al'atus) cavernosus Tkoschel. 1S51. Über die Gattung Tripylus. Arch. f. Naturgesch. XVII. 



I. p. 72. 



— ■ — australis — — Iljidem. 



Faorina cavernosa Gray. 1S55. Catalogue of recent Echinida, p. 57. 



— australis — — Ibidem. 



(?) Hcmiaster cavernosus A. Agassiz. 1881. >Challenger> Echiiioidea p. 177 (pro partel. 



