. I n n Fig. 4. Diagrammatic reconstruction of the right half of the fore-gut of Nebaliopsis typica in three sections (I-III). anterior horn; anterior median projection; dorsal ridge; glandular region; /. labrum; lateral thickenings; pa. paragnaths; plated walls. MUSCULATURE The similarities between the musculature of the fore-gut of Nebaliella and that of Nebalia are very striking, as the diagrams (Figs. 6 A, B) show. Differences are that the lateral dilator muscles {) of the oesophagus have five points of insertion as compared with two in Nebalia. The
. I n n Fig. 4. Diagrammatic reconstruction of the right half of the fore-gut of Nebaliopsis typica in three sections (I-III). anterior horn; anterior median projection; dorsal ridge; glandular region; /. labrum; lateral thickenings; pa. paragnaths; plated walls. MUSCULATURE The similarities between the musculature of the fore-gut of Nebaliella and that of Nebalia are very striking, as the diagrams (Figs. 6 A, B) show. Differences are that the lateral dilator muscles {) of the oesophagus have five points of insertion as compared with two in Nebalia. The muscle corre- sponding to the small median projection muscle is greatly enlarged. The anterior dorsal dilators () are also enlarged but the posterior dorsal dilators () are reduced, though there is a great thickening of the chitin at their point of insertion. The strong circular muscle (cont.) which is so conspicuous in Nebalia is present in Nebaliella also, though slightly reduced. No muscles could be found in the groove between the anterior horns of the stomach where Nebalia has a few thin strands of fibres.
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
