IIG ME. r. II. CARPENTER ON THE GENUS ACTINOMETRA. 



DESCRIPTION OF THE PLATES. 



The followiug letters denote the same parts throughout all the Plates. 



A, B, C, D, E. The five Radii or Ambulacra. 



Ai, A^, Bi, Bo, C\, C.,, Di, D„, £„ E,. The ten Primary Arms. 



a.c. Axial ccelom. a.p. Axial prolongation. 



a.i.c. Axial interradial canal. a.r.c. Axial radial canal. 



a.i.f. Axial interradial furrow. a.r.f. Axial radial furrow. 



An. Anal tube. 



bi, b.2, bs, bf„ biQ. First, second, third, sixth, and tenth brachials. b.b. Basal bridge. 



b.f. Basal fold. b.g. Basal groove. 



b.My JMuscles between the radial axillary and the first brachials. 



i.jWj. Muscles between the second and third brachials. 



c.c. Central canal of the calcareous segments of the rays and arms. 



c.d. Central canal of the eirrhus-segments. ch. Chambers of the quinquelocular organ. 



cd. Centrodorsal piece. dr. Cirrhus. 



cd.c, Centrodorsal coelom. cl. Clavicular. 



c.n. Calcareous network in the central vacuity of the pentagonal base of the calyx. 



co.c. Commissural canals in the first radials. d.i.f. Dorsal interradial furrow. 



cv.c. Circum visceral ccelom. d.r.f. Dorsal radial furrow. 



rfj, d^, d.a. Fii'st, second, and axillary distiehals. ep. Epithelial wall of the alimentary canal. 



F. Central funnel-shaped space enclosed within the pentagonal base. 



/. Muscular fossse. g. Vertical lamella of the calcareous segments. 



/j. Intermuscular furrow. (ji. Their superior margins. 



f^. Notch representing it in Ant. celtica. g^. Their inner lateral margins. 



g^. Ridge formed by the union of these in the first radials of Ant. celtica. 



h. Foss£E lodging the intcrarticular ligaments. 



i. Transverse articular ridge. i.co. Interradial commissure. 



i.e. Interradial elevations on the centrodorsal piece. 



iv.c. lutcrvisccral ecclom. j. Fossaj lodging the clastic ligaments. 



k. Fossai lodging the ligamentous substance between the sides of the second radials. 



L. Ligamentous substance between the sides of the first radials. 



I. Ligamentous substance between the fii-st radials and the centrodorsal piece. 



L'. Incompletely decalcified portions of the skeleton. 



Z/,. Intcrarticular and "1 ligaments between the first and second radials, or second and third 



l^. Elastic J brachials. 



Lj. Intcrarticular ligaments between the second and third radials. M. IMouth. 



N. Fibrillar nervous envelope of the quinquelocular organ. 



n. Axial nervous cords of the rays and arms. o. Interradial spout-like processes of the rosette. 



n'. Their branches. o'. Interradial triangular processes. 



n.c. Axial nervous cords of the eirrhi. o.b. Ovoid bodies. P. Peristome. 



Pe. Uncalcified pcrisome between the radii. /;. Radial processes of the rosette. 



p . Small curved processes at the sides of a single basal. 



pi,p^,p.a. First, second, and axillary palmars. 



Q. Radial openings on the dorsal surface of the pentagonal base. 



