124 BULLETIN OF THE 



DESCRIPTION OF PLATES. 



PLATE 1. 



Fig. 1. |. Vertical cross-cut through a part of the disk of a female Gorgonocephalus 

 Pourtalesii, and through one arm not quite parallel to its axis, exposing a section 

 of the mouth-frame,/, and of the aim-bones, w': — r, mouth-tentacles; d, mouth- 

 papillae ; d u, mouth-sphincter, above which is the passage into the stomach, S(, whose 

 floor has a stout attachment to the open angle of the mouth frames, leaving a large 

 ring, df, which gives free communication between the radiating com])artments of tlie 

 bodj'-cavity. Above and beyond the cavity of the stomach are the stomacli-pouches, 

 St', St", which are attached at their outer ends to the roof of the disk-wall, and to 

 the inner points of the ovarial lobe, 5. 



Fig. 2. J. Vertical section of a part of Gorgonocephalus Pourtalesii just above the 

 mouth, showing a portion of one brachial and two interbrachial spaces of the body- 

 cavity, looking from the centre outward. The stomach is cut away along its floor, St, 

 and again above, where it passes into the thin-skinned lobes, St", St", which have pow- 

 erful attachments below at the outer open angle of the mouth-frames. In the centre 

 is the inner end of the arm, A m, to whose u})per side is strongly attached a stomach- 

 pouch, St'. These pouches have therefore ten strong attachments round the mouth, five 

 brachial and five interbrachial. In their midst, like a cylindric bag, rises the base of 

 the stomach proper, which leaves between its wall and these attachments a large an- 

 nular space, giving free communication from the radiating compartments of the 

 body-cavity to outer surfaces of the stomach-pouches and the ovarial lobes. Thus, an 

 egg from any of the ovarial lobes could pass out by any one of the ten genital 

 openings. 



Fig. 3. ^. A horizontal cross-cut through a part of the disk of Gorgonocephalus 

 Pourtalesii, just above the arms, and passing through the outer ends of the radial 

 shields, I, I, the ovarial lobes, 5, 5, and the stomach-pouches, St", which radiate 

 from the stomach, S/, and adhere by their outer ends to tlie inner points of the ovarial 

 lobes, 5, 5. These adherent ovarial lobes and stomach-pouclies are arranged in ten 

 radiating groups, wliich are attached also below (compare Fig. 2), and thus divide 

 tlie body-cavity into ten radiating compartments, cacli emptying outwardly by a gen- 

 ital opening, no, and communicating witliin, by a ring-tube (5/, Fig. 1), with the 

 other compartments. The stomach-pouches are usually filled with a coagulated, 

 pasty substance, while the stomach proper is empty. 



Fig. 4. -^i". Cross-cut of the inner end of an ovarial lobe of Gorgonocephalus Pour- 

 talesii showing the egg-clusters and the enclosing membrane, which is thickened at 

 its extremity. 



PLATE II. 



Fig. 5. 5. Vertical cross-cut of Euryale aspera, including three arms, one mouth- 

 angle complete, and sections of two others, /. At the ends are two nmch dilated 



