66 
TH. MORTENSEN. 
(Schwed. Südpolar-Exp. 
Abatus , as will be shown later on. For the present this form may be left out of con- 
sideration, as also the Schizaster ( Brisaster ) Moseleyi A. Ac., while there will be 
reason to discuss the Schizaster ( Tripylus ) Philippii (Gray) together with the other 
species mentioned above. 
There have thus been established no less than 8 species of the » Heiniaster» (Aba- 
*A)-group from South America viz.: Tripylus excavatus Phil., cavernosas Phil., 
australis PHIL., Faorina antarctica Gray, Abatus Philippii LovÉN, Hemiaster Agas- 
sizii PFEFFER, IL gallegosensis De Loriol and FI. elougatus KOEHLER, which have 
been regarded as synonyms in different ways, even made one species altogether 
(except gallegosensis and elongatus , which have evidently only their recent date to 
thank for not having likewise been made synonyms of cavernosas'). To these must 
be added the Kerguelen-species, cordatus , likewise generally regarded as a synonym 
of cavernosus. It was then very desirable to have all these forms thoroughly re- 
examined, and the Swedish South Polar Expedition has given me the occasion to 
undertake that work. Though the material collected by this Expedition is rather 
large (the collection of the Swedish Fuegian Expedition 1895 — 97, likewise placed 
at my disposal, contains only little material of these forms), it would not suffice for 
a thorough revision of the whole group. I have therefore made every effort to get as 
much material as possible, and especially to have the type specimens reexamined. 
Everywhere I met the greatest liberality, for which I may express my deep gratitude. 
Professor LUDWIG sent me the co-types of Philippi’s Tripylus excavatus , australis 
and cavernosus; Prof. ThÉEL sent me the type of LovÉn’s A ba tus Philippii, together 
with some other specimens identified by LovÉN. From Prof. JOUBIN I have received 
one of Bernard’s specimens, and from Dr. Meissner I received some of the spe- 
cimens mentioned by him in his paper on the Chilenian Echini. De LORIOL sent 
me a pair of specimens of his Hemiaster gallegosensis , and from the Hamburg Mu- 
seum I received the types of Pfeffer’s Hemiaster Agassizii together with the whole 
rich material of South American Spatangoids contained in the collections of this 
Museum. Further I have examined in the British Museum the type specimens of 
Gray’s Faorina antarctica and the specimens from the »Challenger», and lastly I had 
the rich material of Abatus cordatus collected at Kerguelen by the German South 
Polar Expedition. It must be conceded, therefore, that I have done my best to 
secure a good basis for my researches on this group of Spatangoids. 
We may first examine the value of the genera Tripyhis and Abatus. (That the 
Abatus- species have no nearer relation to Hemiaster , with which genus they have 
for so long time been associated, I think I have shown definitely in »Die Echinoiden 
d. deutschen Südpolar-Expedition» p. 90 — 91, the main differences being 1) that in 
Abatus the apical system is ethmolytic, with 2 — 3 genital openings, while in Hemi- 
aster it is ethmophract, with 4 genital openings, and 2) that in Abatus a latero-anal 
