36 EMBRYOLOGICAL MONOGRAPHS. 
PLATE XII. 
Development of EcutnoweEa, continued. Figures from Avexanper AGassiz and C, WrvitLe 
THoMsON. 
YouNnG STAGES OF 
1-3. Goniocidaris canaliculata. 17-22. LEchinarachnius parma. 
4. Dorocidaris papillata. 23, 24. Encope emarginata. 
5, 6. Asthenosoma hystrix. 26-29. Conolampas Sigsbet. 
7. Diadema setosum. 30-35. Hemiaster cavernosus. 
8-12. Mellita sexforis. 36, 36’. Spatangus purpureis. 
13-14. Mellita testudinata. 37-40. Brissopsis lyrifera. 
15, 16. Mellita longifissa. 
1-3. Goniocidaris cunuliculata. From Alexander Agassiz, The Zoology of the Voyage of H. M. S. Challenger, 
Vol. III. Part [X. Report on the Echinoidea, Pl. II., London and Edinb., 1881. 
. Young specimen, 2mm. in diameter, seen from the abactinal side. 
. The same as fig. 1, seen from the actinal side. 
. Another young specimen, 3 mm. in diameter, belonging to the long spined type of the species. 
mm Whe Re 
. Dorocidaris papillata. From Alexander Agassiz, Revision of the Echini, Part II., 1872, Pl. Ile. Ill. Catal. 
Mus. Comp. Zoél., No. VII. Part II., 1872, Pl. IIs. 
4. Young specimen, seen from the abactinal side, partly denuded. 2.4 mm in diameter. 
5, 6. Asthenosoma hystrix. From Alexander Agassiz, Revision of the Echini, Part II., 1872, Pl. Ils. 
Quoted above. 
5. Part of test of young specimen, measuring 3.1 mm. in diameter, seen from the abactinal side. 
6. Part of test of same, seen from the actinal side. 
7. Diadema setosum. From Alexander Agassiz, Revision of the Echini, Part II., 1872, Pl. II. Quoted above. 
7. Young specimen, measuring 2.4mm. in diameter, seen in profile, showing the anal tube projecting between 
the spines beyond the level of the abactinal surface. 
8-12. Mellita sexforis. From Alexander Agassiz, Revision of the Echini, Part II., 1872, Pl. XI. Quoted above. 
8. Young specimen, 2.4mm. in diameter, having a Laganum-like shape ; the posterior interambulacral lunule is 
not as yet to be seen from the abactinal side. 
9. The same from the actinal side, deeply concave, showing the commencement of the posterior interambula- 
eral lunule. 
10. Young specimen, 4mm. in diameter, seen from the abactinal side ; first trace of the posterior lunule on the 
abactinal side. 
11. Young specimen, measuring 10.1 mm. in diameter, from the abactinal side. The ambulacral lunules all pres- 
ent, in different stages of growth. 
12. Young specimen, measuring 12.7mm. in diameter, with all the ambulacral lunules completely pierced 
through and well formed. 
3-16. Mellita testudinata and longifissa, in which the lateral lunules are formed from notches in the edge of the 
test. From Alexander Agassiz, Revision of the Echini, Part II., 1872, Pl. XI. Quoted above. 
13, 14. Mellita testudinata. 
13. Posterior interambulacrum of fig. 14, showing the posterior interambulacral lunule, which in this type is 
formed from the lower side, as in M. sezforis, and forces its way through the test to the abactinal surface. 
14. Young specimen ({), seen from the abactinal side ; the edge of the test shows as yet no trace of the notches 
so well developed in fig, 15. 
