ACTINOrODOUS HOLOTHUEIOIDEA. 



101 



it, is that referroil to in Bell's description. In life the append- 

 ages are longitudinally elongated but in alcohol transversely elon- 

 gated, as described by Bell. This seems to be a difference duo 

 merely to the state of contraction. 



There are three kinds of calcareous bodies. ( i ) Tables in a 

 very closely arranged layer (textfig. 20 h, c). They have a disk 

 with smooth margin. Around the largo central opening there is a 

 very neat circle of small holes, ±1-2 in number. Of these the 

 four in the radii of the spire-pillars are often larger than the 

 others. The size of the disk 0.05 — O.OG mm. Tlie spire is built 

 of four pillars with one cross beam. The crown has ± 12 

 teeth, (ii) Buttons in a layer below that of the tables. Most 

 mimerous are the regularly shaped buttons with three 

 pairs of holes (r/). Some others show four or ii\(^ pairs 



of holes. Some more or less crenate 

 in the margin, others not. Not un- 

 commonly the holes arc asym- 

 metrically present in thut either 

 one or more of them on one side 

 have run together, or one is altogeth- 

 er without a vis-a-vis on the op- 

 posite side. The buttons measure 

 0.00— 0.07C) mm. m length. The 

 above tables and buttons must be 

 considered as agi-ceing well with 

 those given in Bell's figures, (iii) 

 Bolow the above mentioned two 

 layers, in the under skin, there are somewhat sparsely scattered, 

 much more minute buttons, only 0.02 — 0.030 muL in size. They 

 are sometimes mere oval rings (/), but more frequently show a 



Textfig. 20. 



Ilolothuria mackari : a — CalcnrDoiis 

 ring ; b, c— T.ibles ; d— Button ; e, f— 

 Small imperfect button?. (6— /x3(10. 

 I — ^InterraclifilLT ; R— Radiiilin. 



