274 



THE VOYACxE OF H.M.S. CHALLENGER. 



upper plate, and from it issues tlie tentacle (r), while below is attached the rough, 

 cylindrical tentacle scale or arm spine. 



In several respects this genus leans towards the Ophiuridse ; as in its large teeth in 

 a single row, its solid radial shields, and its weU formed under arm plates. 



Table of Species of Astroschema. 



r^ ,— < 



CO O - i 



^ a ^ ) 



c3 § cd 



r- -^ ^ 



s ^ 





^ -s 



-5 =«• 



Diameter of 



Disk to leiigtli 



of Ann. 



1: 15 



1 :17 



1 :17 



arm 

 moderate. 



1 :15 



1 : 10 

 1 :1.3 



1 :15 



arm long 



1 :33 

 1 :24 



1 :24 



Width of Arm 



to diameter 



of Disk. 



Grains in 



1 mm. long 



on upper arm 



at its base. 



1 :3 

 1 :3 



l:3i 



1 :2| 

 1:2^ 



1 :3 



1 :3h 



1 :3 



1 :4 

 1 :4 



1 :7 



4-5 



9-15 



6-7 



12 



8-9 

 6-9 1 



Disk spines set on little plates whicli 

 jaave the disk and arms. 



Disk grains sliarji, even far out on 

 arms. Tentacle scales not any- 

 where longer than a joint, and 

 scarcely clubbed. 



Grains far out on arras, rounded. 

 Tentacle scales often as long as H 

 joints, but scarcely clubbed. 



Disk grains close-set, smooth, and very 

 large. 



Disk grains very fine, smooth, and 

 even. Two tentacle scales do not 

 begin till beyond the eighth pore. 



Arms short. Disk flat and even. 

 Under tentacle scale at end of arm 

 becomes a compound hook. 



Mouth tentacles in tubes. Lower 

 tentacle scale, near end of arm, 

 very long but not clubbed. 



Disk grains spaced and arranged in 

 concentric lines. 



No tentacle scale till fourth pore, then 

 one till the twelfth, after which 

 two (an iU-defined species). 



Arms extremely long and thin 



Arm much higher than wide. 



Astroschema horridum. 

 Astroschema oligactes. 



Astroschema tumidum. 



Astroschema arenostim. 

 Astroschema heoe. 



Astroschema sal/x. 



Astroschema ruhrum. 



Ast)-osch ema steenstrupil. 

 Astroschema sulcatum. 



Astroscliema teiiue. 

 Astroschema hrachiatiiw. 



Astroschema inteetum. 



