OF THE ACALEPH^ OF NORTH AMERICA. 369 



p. Horizontal bundles of muscles extending between the vertical rows of combs and the main muscular bundles. 



f. Diverging fibres of the main muscular vertical bundles, forming a kind of sphincter around the tube leading into the 

 cavity of the tentacular apparatus. 



q. The main trunk from which the eight radiating chymiferous tubes arise. It should be noticed that these tubes are 

 not strictly in the same horizontal plane, since their respective position varies more or less in the different contractions of 

 the body, and those on one side are successively higher than those of the opposite side in the alternate contractions of the 

 opposite halves of the body, which regulate the general circulation of the nutritive fluid. 



r. The chymiferous tubes following the digestive cavity. They arise from the main horizontal tube, and extend to the 

 margin of the mouth, following the middle of the flat surface of the digestive cavity. 



s. Eight narrow tubular prolongations of the vertical chymiferous tubes, which taper at the summit of the vertical rows 

 of locomotive combs, and extend towards the centre of the circumscribedj area, where they empty into the vertical funnel 

 of the main chymiferous cavity. 



t. Prolongation of the main vertical bundles of muscular fibres towards the circumscribed area, which follow the course 

 of the narrow prolongation of the vertical chymiferous tubes, diverging like pennate muscles. 



u. Combs of locomotive fringes. 



V. Vertical chymiferous tubes, which accompany on the inner surface the rows of locomotive combs. 



v'. Areolar space upon the inner surface of the vertical chymiferous tubes, from which the eggs are probably developed. 



10. Base of attachment of the locomotive combs, from which the isolated fringes arise, and to which the muscular fibres 

 moving these fringes are attached. 



X. Ganglion, probably of a nervous character. 



y. Ganglion-like bodies, arising probably from the accumulation of granules in the contracted state of the vertical 

 chymiferous tubes when the circluation has ceased. 



z. Free granules moving in the vertical chymiferous tubes. 



a. Chymiferous tubes of the tentacular apparatus. 



a'. The opening through which the vertical chymiferous tubes of the tentacle open into the main horizontal chymif- 

 erous tubes between their main forks. 



/3. Swollen margin of the elongated disk from which the tentacles arise. 



y. Medial keel arising from the summit of the elongated disk of the tentacle, and extending to the base of the 

 tentacle itself. 



8. Eye-speck in the centre of the circumscribed area. 



t. Circumscribed area. 



('. Raised line following the inner outline of the circumscribed area, probably the analogue of that row of fringes so 

 conspicuous within the circumscribed area in some other genera of Beroid Medusae, and particulariy distinct in the genus 

 Idya. 



(". Another line parallel to the former, and within it, the special nature of which I have failed to ascertain. 



f. The openings of the two bulbs of the vertical funnel through which the fecal matters are occasionally discharged. 



rj. Revolving bulb of fecal matter. 



6. The tubercle upon which the eye-speck, 8, rests. 



t, K. Concentric swellmgs connected with the ganglion of the eye-speck, stretching iii the direction of the longitudinal 

 diameter of the circumscribed area. 



X. Four ganglionic swellings within the inner of the swollen margins near the ganglion of the eye-speck, the nature 

 of which I have also failed to determine. 



/i. Longitudinal muscular fibres of the main thread of the tentacle. 



V. Longitudinal fibres of the fringes arising from the sides of the tentacle extending across the main thread, where they 

 appear as transverse fibres. 



^. Coating of heterogeneous cells all round the main thread and its lateral fringes. The larger ovate cells are lasso-cells. 



50 . 



