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THE RECENT CRINOIDS OF AUSTRALIA — CLARK. ^fifc. 



Keys to the Families, Genera, and Species of Australian 



Crinoids. 

 The following keys have been arranged so as to make as easy 

 as possible the work of identifying Australian Crinoids. The most 

 obvious and most readily comprehended differential characters 

 have been employed, regardless of their systematic value. Besides 

 general keys, I have included keys based upon the extent and 

 character of the arm division which, although purely a matter of 

 secondary significance, offers possibly the best criteria to those 

 not especially familiar with these animals for the identification of 

 the various genera and species. 



It must be borne in mind that the young of all multibrachiate 

 Comatulids have ten arms only, and that, therefore, these keys are 

 not adapted to them. In general there will be no difficulty in 

 identifying the young by comparison with adult specimens of the 

 species inhabiting the localities where they are found ; but in the 

 Tropiometridse and Thalassometridse the young differ widely from 

 the fully grown, and great caution must be used in their deter- 

 mination. 



Key to the Families and Subfamilies of Crinoids inhabiting thk 

 Coasts of Adstralia. 

 o^. Proximal pinnules furnished with a terminal comb ; mouth 

 usually marginal or submarginai, anal tube central (10-160 



arms) .„ Comasteridce. 



«*. Proximal pinnules without terminal comb ; mouth central, anal 

 tube marginal. 



&^. I Br united by pseudo-syzygy (5 100 arms) Zygometridce. 



b^. I Br united by synarthy. 



c^. Pn absent (10-30 arms) Colobometridce. 



c'. Pa present. 



d'. All the pinnules cylindrical and very slender ; P^ twice 

 as long as the next following pinnules ; all tlie pin- 

 nules are composed of much elongated segments (10 



arms) AiitedonidoR. 



d'^. Some of the lower, or all the pinnules prismatic, or 



some of the lower pinnules enlarged and stout ; Pi 



smaller than Pg ; or, if larger, strongly prismatic. 



«i. The pinnules, at least those in the lower portion of 



arm, triangular. 



f^. All the pinnules strongly prismatic ; cirri very 



long, the outer segments short and bearing dorsal 



spines ; P^ similar to P^ but smaller, or much 



enlarged and strongly prismatic (10-30 arms)... 



ThalastometridtE, 



/*. The distal pinnules slender and cylindrical, 

 shorter than the triangular middle pinnules; 

 cirri short and stout, the distal segments with- 

 out dorsal processes ; P^ similar to P2, but 



slightly shorter and more delicate (10 arms) 



Tropio7netrid(V . 



