7G Transactions of the [''Z^,^'!'^%Ti^ 



V. — On the Calcareous Spicula of the Gorgonacem: their Mo- 

 dification of Form, and the Importance of their Characters 

 as a Basis for Generic and Specific Diagnosis. By Wm. S. 

 Kent, F.Z.S., F.R.M.S., of the Geological Department, British 

 Museum. 

 (It'cad hffure the Koyal MicROSCOricAi, Society, January 12, 1870.) 



The "Subject of the present communication may be considered as 

 one of pecuhar mterest to workers with the microscope, embracing 

 as it does forms of exquisite outhne only to be appreciated with the 



EXPLANATION OF PLATE XLI. 



Figs. 1-8. — S(iuamo«e spicula of Primnoa lepadifera X 50. 

 „ 4-7. — „ „ „ monilis „ 



„ 8, 9. — „ ,, „ Tcrticillaris „ 



(The last closely assimilating the form of scale iDCculiar to the 



Ctenoid fishes.) 

 „ 10-12. — Squamose spicula of Primnoa plumatilis x 50. 

 „ 13. — Unsymmetrical irregular fusiform spiculum of Muricca echinata x 50. 

 „ 14, 15. — „ „ „ spicula of Mur. lima. 



„ It), 17. — ,, arcuate, and echinato-clavate spicula of Eunicea plan- 



tujinm, Val. {Muricea), x 50. 

 „ 18, 19. — Laminato -proliferous and echinato-arcuate spicula of i2/t«p«c?ir/o;-(/8a 



stricta, M. Edw. (^Echinogoiyin), x 100. 

 „ 20, 21. — Laminato-proliferous and bi-aliform spicula of Muricca fungifcra, 



M. Edw. (Echinuijorgia), x 100. 

 „ 22, 23. — Laminato-proliferous and bi-rotulate spicula of lihip. coarctata, 



M. Edw. {Ecldnogorgia'), y. 100. 

 „ 24. — Laminato-frondose spiculum of Gorgonia granifera, Lamk. (^Echino- 



gorgia), x 100. 

 „ 25. — Inflato-proliferous spiculum of Lcptogorgia aurantiuca, M. Edw. (_Gorg. 



Danaidis, Val.) {Echinogorgia i\ x 100. 

 ,, 26, 27. — Irregular laminato-proliferous si^icula of Paramuricea placomus, var. 



a, Klk. (Acant/iogorgia), x 50. 

 ,, 28-31. — Laminato-proliferous, attenuato-arcuate, and irregular fasciculate 



fusiform si^icula of Paramuricea placomus, var. b, Klk. (^Acaiitko- 



gorgia), x 50. 

 „ 32, 33. — Irregular proliferoiis fusiform spicula of Acanthogorgia Gragi, John- 

 son, the iirst one exliibiting a tendency to become fasciculate 



at one extremity, x 50. 

 „ 34, 35. — Symmetrical tuberculate fusiform, and echinato-clavate spicula of 



Eunicea laxispina, M. Edw. Fig. 34 x 50, and 35 x 100. 

 ,, 3G, 37. — Symmetrical tuberculate fusiform, and echinato-clavate spicula of 



Eunicea muricata, M. Edw. Fig. 3G x 50, Fig. 37 X 100. 

 ., 38. — Laminnto-clavate spiculum of Plexaura pendula, Val. (^Eunicea), x 100. 

 „ 39. — Symmetrically tuberculate .spiculum of an unknown species, probably 



belon;^iiig to the genus Eunicea, x 50. 

 ,, 40-43. — Proliferous fusilbim, and attenuato-stellate spicula of Plexaura 



porom, M. Edw., x 100. 

 „ 44. — Bi-stellate spiculum of the same species x 100. 



45-46. — Proliferous fusiform, and bi-stellate spicula of Plexaura fucusa, 



M. Edw., X 100. 

 „ 47-50. — Bi, tri, and quadri-partitc tuberculate spicula of Plcxaur.ella 



dichotoi/iii, Klk., X 10(1. 

 „ 51. — Attenuato-quiidranguliir spiculuin from the same speciLS, almost devoid 



of tubercles, x 100. 



