149 



PLATE 



II. Pentacrinus Caput Medusa;, p. 51. 



All the figures, with the exception of 18. to 22. are considerably larger thin natural, 



I. Pentacrinites Briareus, p. 56. 



II. Pentacrinites Briareus, p. 57. 



I. Pentacrinites subangularis, p. 59. 

 f Pentacrinites subangularis, "I 

 I Pentacrinites basaltiformis, J P* 



Pentacrinites tuberculatus,* p. 64. 



Genus. Poteriocrinites, p. 67. 



Poteriocriuites crassus, p. 68. 



Poteriocrinites tenuis, p. 71. 



Genus. Platycrinites, p. 73. 



I. Platycriniles laevis, p. 74. 



II. Platycrinites lacvis, p. 75. 



Fig. 33. to 51. larger than natural size. 



Platycriuites rugosus, p. 79. 

 f Platycrinites tuberculatus, 1 

 j Platycriuites granulatus, 



1 Platycriuites striatus, 



I Platycrinites pentangularis, J 



Genus. Cyathocrinites, p. 85. 



Cyathocrinites planus, p. 86. 



Cyathocrinites tuberculatus, p. 88. 



Cyathocrinites rugosus, p. 90. 



Cyathocrinites quinquangularis, p. 92. 



Genus. Actinocrinites, p. 94. 



I. Actinocrinites triaconta dactylus, p. 96. 



II. Actinocrinites triaconta dactylus, p. 98. 



III. Actinocrinites triaconta dactylus, p. 99. 



* I regret, when describing Pentacrinites tuberculatus, not to have stated particularly that 

 its columnar joints when not fully formed, are like those of other Pentacrinites, considerably 

 lliinnrr than at a subsequent stage of growth, and alternately larger and smaller. I should also 

 hare further observed, that the exterior surface of the joints which, in the older specimens, as 

 represented in the plate, is studded with irregular tubercles, has in these young and thinner ones 

 only a single row of such tubercles ranging regularly round the middle. The cause of this appears 

 to be that as these tubercles arise from the contraction of the investing muscular membrane, they 

 are therefore more regular and distinct in the earlier and non-cartilaginous state of the joint. 



X 



