Bd. VI: 4) THE ECHINOIDEA. 1 3 



zontal sutures so characteristic of Goniocidaris (though in large specimens of Gonio- 

 cidaris the vertical sutures are also deepened); also the pedicellariae are different — 

 especially the long end-tooth of the small globiferous pedicellariae in Goniocidaris is 

 a characteristic difference from Austrocidaris. — The nearest relation of Austrocida- 

 ris probably is the genus Eurocidaris, established for the Kerguelen-species nutrix, 

 so long erroneously confounded with canaliculata. * The characters distinguishing 

 these two genera have been pointed out in my sEchinoiden d. deutschen Siidpolar- 

 Expedition» (loc. cit.), to which I may refer. 



Though both AGASSIZ and DODERLEIN have given descriptions of this species, 

 the maintaining of E. nutrix as a distinct species — even of another genus — and 

 the establishing of the new species of Austrocidaris described below make a renewed 

 detailed description of canaliculata highly desirable. 





Dia- 

 meter. 



Height. 



Apical 

 system. 



Anal 

 system. 



Peri- 

 stome. 



Width of 



Plates of 



Longest 

 Radioles. 



Remarks. 



Ambu- 

 lacra. 



Intcr- 

 ambul. 



Ambu- 

 lacra. 



Inter- 

 ambul. 





m m . 



m 111 . 



mm. 



mm. 



mm. 



mm. 









mm. 





9 



26 



1 5 



10.5 



7 



10.8 



3 



12.5 



38-39 



8 



'9 





d" 



21 



10.5 



8.5 



5-5 



9 



2.8 



9-5 



30-31 



7-8 







& 



20(19.5) 



10 



8.8 



5 



9 



2.6 



9-5 



29 



7 





A little oblong. 



9 



17.8 



9 





5 



8.8 



2 



8 



27-28 



7 







cT 





7 



6 



3-8 



7-5 



2 



6.8 



23-24 



6-7 









9-5 



5 



4-5 



2.8 



5 



1-3 



4.8 



I7-I8 



6 









8.2 



4 



4 



2.2 



4.2 



1 



4 



14-15 



6 





No genital 





7 



3-5 



3-2 



2 



3.8 



1 



3.2 



12-13 



6 





openings. 





5 



2-5 



2.8 



1 3 



2.8 



0.9 



2.1 



9—IO 



5-6 



n 







21 

























18 

















— 



12 







17 



















20 







16 

























15 



















12.5 







»4-5 

























The test (Pi. 



IV Figs. 4— 



-6, 8— 



11) is 



rather 



low, the heig 



ht generally not ex- 



ceeding half the horizontal diameter. The abactinal side is flat, or even — especially 

 in the females — considerably sunken. The actinal side is flat, the edge of the 

 peristome not incurved; the sides of the test beautifully rounded. 



The ambulacra (PI. XIV Fig. 1) are about one fourth as wide as the inter- 

 ambulacra; the poriferous zone is a little narrower than the non-poriferous part of 

 the plates. The primary ambulacral tubercles are rather conspicuous; inside these 



* It is worth remarking that Wvv. Thomson, the author of nutrix, regards it as generically different 

 from canaliculata, referring the former to the genus Cidaris, the latter to Goniocidaris; this course is also 

 held by Studer in his >Ubersicht d. Gazelle-Echinoiden>. (Comp. also Meissner, Op. cit. p. 4.) 



