DEVELOPMEIS'T OF AXTEDOX (COMATULA, LAMIC.) ROSACEUS. 751 



Fig. 3. Long-it udiiKil section of" the terminal portion of a Dorsal C'irrhus ; showing the 

 claw articulated by the plane surface cut through at a, a, to the penultimate 

 segment, and the movable articulation h, b, in which the fossaj for the lodg- 

 ment of the ligament are much larger and deeper on the aboral side ; at r, c 

 is shown the central canal, which is continued into the cavity of the claw. — 

 Magnified 70 diameters. 



Fig. i. Section of Centro-dorsal plate taken in a plane parallel to its flattened surface ; 

 showing at b, b the canals leading to the articular sockets. — Magnified 

 70 diameters. 



PLATE XXXVL 



In this Plate are shown the First, Second, and Third BadiaJ.'i, and the First, Second, 

 Third, Fourth, and Yifth. Brachuds, oi Antedon rosaccus; their different aspects being 

 designated (except in fig. 1) as follows: — 



A, internal or proximal face. 



B, external or distal face, 

 c, ventral or superior face. 

 ]), dorsal or inferior face. 

 E, lateral face. 



The following References are common to the entire series : — 

 «, a. Articular Eidges. 

 h, b, Fossa; for Interarticular Ligaments. 



c, c. Muscular Fossa?. 



d, d. Vertical Lamellte. 

 e, Axial Canal. 



y, y, Fossa for Elastic Ligament. 

 ]}, Articular Socket of Pinnule. 

 sg, Syzygy. 

 The magnifying power for all the Figures is 15 diameters. 

 Fig. 1. First Pvadial : on its internal aspect (b) are shown the apertures, c, e, of the two 

 passages by which the Axial Canal originates, and the apertures, g, g, of the 

 circular passage by which the axial canal of each Ray communicates with the 

 canal of the Ray on either side ; h, furrow between the prominent margins of 

 the apertures e, e ; ?, i, smooth inclined faces, closely adherent to those of 

 the First Eadials on either side : A, external face. 

 Fig. 2. Second Radial. 



Fig. 3. Third or Axillary Radial; d', vertical ridge dividing the two articular faces. 

 Fig. 4. First Brachial. 

 Fig. 5. Second Brachial. 



Fig. 0. Third Brachial, united in c, d, and e with the Fourth. 

 Fig. 7. Fourth Brachial. 

 Fig. 8. Fifth Brachial. 



MDCCCLXVI. 5 K 



