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PROCEEDINGS OF THE 



[Dec, 1856. 



its greatest development; it spreads also downwards over the seve- 

 ral lobes, but in this portion the cells are very much smaller. 

 Around the tubes the cells are of a somewhat pyramidal form, 

 their bases turned outwards, the apices inwards, to meet the chy- 

 miferous canal. The substance which fills them is not at all unlike, 

 in appearance, the white of a fresh egg. I have discovered no 

 granules in it, nor any appearance of fluidity. Indeed, I feel quite 

 sure that there are no cavities within the cells, and no communi- 

 cation, consequently, between them and the radiating tubes. The 

 only changes visible in the appearance of the part, are those pro- 

 duced by contraction, of which it seems capable to a very conside- 

 rable degree. 



The lower portion of the proboscis is occupied by the stomach, 

 the form of which, from the opacity of its walls, cannot be per- 

 ceived. Judging from the four-lobed character of this part, how- 

 ever, it is likely that its cross-section would be quadrangular. The 

 walls are colored a somewhat orange yellow in the lobes; with 

 lake in the interstices. Directly overlying the walls of the stomach 

 is the sexual glandular layer, not apparently continued around the 

 whole organ, but only occupying the four lobes. The sexual pro- 

 ducts are thus developed between the proper wall of the stomach 

 and the external layer of clear cells already spoken of, as the con- 

 tinuation of that around the origin of the vertical tubes. I have 

 never been able to discover the outlets of thess organs, and am, 

 consequently, ignorant of the manner in which their products 

 escape. There appears, also, to be no tangible difference, in form 

 between the males and females — the only test I have been, up to 

 this time, able to discover, being the obvious one of the presence 

 or absence of ova. Yet this I am sure cannot be wholly relied on, 

 since there is, in all probability, a period when the female having 

 the eggs very small, presents scarcely a difference in appearance 

 from the male, and so far I have never obtained a view of the sper- 

 matozoa, or their developing cysts (if such exist) in any specimen. 

 This portion of the proboscis is as contractile as any other portion 

 of the animal, and when both ovaries and stomach are empty, may 

 be puckered up so as to appear a mere border to the clear mass 

 above. See fig. 25a, PL 5. 



The tissues of the proboscis are gathered together below this 

 stomachic bulb, to form a short narrow neck, from the lower part 

 of which spring four leaflike appendages or labial tentacula of 

 very graceful outline. Each one of these corresponds to the 



