Fig. 1. — A quadrant of the umbrella, subumbral view, natural size (the only portion of this 

 species preserved). The greater part of the principal intestine (especially the whole buccal stomach, 

 fig. 3) was torn away. An opened funnel cavity (ib) of the basal stomach (gb) is visible in the middle 

 of the upper third of the figure. We see the torn, folded subumbral wall of the funnel cavity, whose 

 ectodermal subumbral surface (qw) is spread out flat to the left, whilst part of its endodermal gastral 

 surface (gb) is turned over. The powerful bush of the enormously developed gastral filaments (fb), 

 which extend from the basal point of the funnel nearly as far as the palatine groove (gk), is visible to 

 the right. The pylorus or pyloric opening (gy) separates the basal stomach from the central stomach, 

 of which only a torn fragment of an obelisk plate (jz) has been preserved, to the right above. In the 

 middle of the figure we see a more complete quadrant of the subumbrella, bounded on either side by 

 the cleft-shaped gastral openings (go). The margins of the latter are thickly beset with filaments 

 (Jg), from which, however, the lowest part with the palatine groove remains free. The interradial 

 cathammal nodes (Jen) gleam through the middle of the subumbral wall of the coronal sinus (at the 

 same time in the centre of the whole figure). The intergenital muscle (mg) is joined to the nodes 

 above the interradial deltoid muscle (md") below. The latter separates the two ovaries (sf). 

 gt Midrib (sterigma) of each ovary, mn Congenital muscle, md Perradial deltoid muscle; md"' its 

 paired marginal bundles. The lower third of the figure gives the subumbral view of the umbrella 

 corona, whose upper boundary is formed by the proximal margin of the coronal muscle (mcS) (which 

 is at the same time the distal margin of the coronal sinus). mc 2 Circular folds of the coronal muscle. 

 mc s Furrows between the folds. mc i Distal margin of the coronal muscle (with numerous small 

 coronal furrows). A sense club (o) with the round ampulla above it is visible in the middle of the 

 margin of the umbrella corona ; three tentacles and three marginal lobes on either side. The subum- 

 bral wall of one lobe (the second from the right) is opened in order to show how the two lobe 

 canals (bl) (separated by the fused clasp) are connected by the U-shaped horseshoe canal (comp. fig. 

 22, PI. XXII.). Three of the seven visible arete of the coronal muscle have been cut away in order 

 to show the complications of the tentacle insertion, mk Eoot muscles of the tentacle, be Velar 

 pouch (axial), be" Avelar pouch (abaxial), the septal fissure by which the two communicate, is 

 visible in the third tentacle (from the left). The fourth tentacle (from the left) is cleft open to the 

 base in order to show the vent cavity with the double valved vent hole (comp. PL XXII. fig. 22, ex). 



Fig. 2. — A bit of the umbrella corona from outside (exumbral view), natural size, mz Zonal 

 muscle in the broad coronal furrow (cc). hi Fused clasp. Ig Gelatinous swelling of the lobes on 

 either side of the clasp. Ip Delicate wing selvedge of the marginal lobes, t Tentacles, o Sense 

 clubs. 



Fig. 3. — Quadrant of the oesophagus or buccal stomach from the inner surface, natural size. 

 gs Palatine groove, gb Palatine nodes, bb Perradial buccal pouches ; bd their lateral wing pouches. 

 ac Interradial fleshy oral columns ; ad their thickly folded adradial wings, am Margin of the 

 mouth. 



