976 REPOKT OF COMMISSIONED OF FISH AND FISHERIES. [50] 



EXPI.A]S^AT10N OF PI.ATES. 



LETTERING, 

 a. Anterior. 



a. Fragment of Echiuoderm test. 

 cav. Cavity. 



cav. b. Cavity inclosed by thick nuiscular walls. 

 cat. p. Cavity of float. 

 col, sub. Subumbral radial elevations. 

 cor. Corona. 

 dis. cent. Central disk. 

 fos. cor. Coronal fossa. 

 fos. rad. Subumbral radial furrow. 

 g. Radial elevation on subumbral side of disk. 

 ga. Stomach. 



gm. Globular enlargements (budsf) 

 {. cor. Internal corona. 

 II). inter. Interradial lobe of stomach. 

 lb. per. Terradial lobe of stomach. 

 vig. Ip. Marginal lappet. 

 nig. p. Marginal prominence. 

 mg. sb. Marginal sense-bodies. 

 mg. 80C. Marginal socle. 

 mm. Muscular wall of the lower portion of the float, or base upon which the botry- 



ordal bodies hang. 

 mus. cor. e. Musculus coronalis externus. 

 wiMS. cor. i. Musculus coronalis internus. 

 mm. delt. Musculus deltoideus. 

 oa. Ovary. 

 or. Mouth. 

 per. Peronia. 



per. 0. Basal conical spur of tentacle. 

 pt. Pteron. 

 pycy. Pneumatocyst. 

 pyt. Polypite. 

 s. Stem. 



sb. Marginal sense-body. 

 DOC. Exumbral socle. These socles are probably homologous with the teniacular 



socles (soc. ta.) and the socles of the sense-bodies (soc. sb.) in Atolla. 

 80C. sb. Socle of marginal sense-body. 

 soc. ta. Socle of marginal tentacle. 

 som. Somatocyst. 

 sr. Sulcus radialis. 

 to. Tentacle. 

 V. Velarium. 



PLATE I. 

 Atolla Bairdli, from exumbral surface. 



