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Show 662 MR. F. J. BELL ON THE ECHINOIDEA. Measurements of Tripneustes esculentus. [June 17, No. 1. 2. 3. 4. 5. 6. 7. Locality. West Indies Nassau (New Provi- Ditto ? ? A. Ag. i.1 A. Ag. iv.1 Absolute diam. in millims. 68 141 148 100 110 28-5 118 Percentage value of Height. 51-4 63*8 50 45 56*3 53-3 56*7 Abactinal system. 12*5 149 135 12*2 163 203 16 Anal system. 66 7 7*4 8 105 9-2 Actinal system. 25 18-8 19 23*2 23 35 22*2 Poriferous. zone. 7*8 8*4 85 8 101 7*7 Measurements of Tripneustes angulosus. No. 1. 2. 3. 4. 5. 6. 7. 8. Locality. Gulf of Suez Gulf of Suez Gulf of Suez 79 Absolute diam. in millims. 29 67 77 89 100 109 58 95 Percentage value of Height. 55 49 545 57-2 56 532 60 .526 Abactinal system. 17.25 16*4 155 15-7 18-5 17-4 14*6 17*9 Anal system. 8-6 10 10 10*5 7*9 Actinal system. 34-5 29-8 24-6 25*3 26 26*2 28*4 252 Poriferous zone. 8-6 8-2 9 8 9 8-2 95 9*4 EXPLANATION OF PLATE XLIX. Dentary Apparatus of Tripneustes. Fig. 1. A pyramid of T. angulosus, showing d, the tooth, e, the epiphysis. 2. Ditto of T. esculentus. 3. Ditto of T. depressus. 1 a. Side view of alveolus of a pyramid of T. angulosus, with e, the epiphysis, d, the tooth. 2 a. Ditto of T. esculentus. 3 a. Ditto of T. depressus. \b,21>, 3 b. Kotuhe of the three species. I c, 2 c, 3 c. Side view of radii. Id, 2d, 3d. Free terminal portion of the radii. 1 I add two measurements from Prof. Agassiz for the purpose of comparison; it will be seen that the second set agree very well with m y results. |