JOURNAL OF MICROSCOPICAL SCIENCE. 



EXPLANATION OF PLATE I, 



Illustrating Messrs. Carpenter and Sladen's papers on the 

 " Apical System and Primary Larval Plates of Echinoderms." 



The following lettering is used throughout all the figures : 

 I. Dorso-central. 2. Under-basals. 3. Basals (shaded dark). 4. Radials. 



5. Orals. I. Primary interbrachial plate, r. Radial shield. T. Termi- 

 nal, an. Anus. re. p. Water-pore, or madreporite. 



Figs. 1 — 9. — A series of figures representing portions of the disc of 



different Ophiurids, to illustrate the variations in the development of the 



apical system, i.e. the rosette of primary plates. All after Lyman. 



1. Ophioceramis clausa. 2. Ophiomusium validum. 3. O. fla- 



bellum. 4. Ophioglypha lapidaria. 5. Ophiomitra exigua. 



6. Ophiozona antillarum. 7- Ophiomusium granosum. 

 8. Ophioglypha minuta. 9. Ophiomusium pulchellum. 



Figs. 10 — 16. — A series of diagrams representing the primitive plates in 

 the larvae of Brachiate Echinoderms, an early and a later stage in the larva in 

 each of the orders being given. 



Fig. 10. — Abactinal aspect of a young Crinoid (Antedon rosacea) shortly 

 before detachment from the stem takes place. After Dr. Carpenter. 



Fig. 11. — Abactinal aspect of an early Crinoid larva (Antedon rosacea), 

 in which the radials are still very small. The stem-joints are represented as 

 telescoped into one another, so as to bring the terminal plate of the base of 

 the stem or dorsocentral (i) into close relation with the basals (3). From 

 P. H. Carpenter. 



Fig. 12. — Abactinal aspect of a young Ophiurid ( Amphiura squamata). 

 After Ludwig, slightly altered. 



Fig. 13. — Abactinal aspect of an early Ophiurid larva (Amphiura squa- 

 mata). From P. 11. Carpenter, after Ludwig. 



Fig. 14. — Abactinal aspect of a young Asterid (Asterinagibbosa). 



Fig. 15. — Abactinal aspect of an early Asterid larva (Asterina gibbosa). 

 From P. H. Carpenter, after Ludwig. 



Fig. 16.— Abactinal aspect of a young Asterid (Zoroaster fulgens). 



