PLUMATELLID^ : ALCYONELLA. 398 



polypes " in one specimen which weighed seventeen ounces, and 

 measured fourteen inches and a half in circumference, "may be com- 

 puted at one hundred and six thousand, and the tentacula at five 

 millions three hundred and twenty thousand ! " The mouth is, as 

 usual, in the centre of the crater formed by the tentacula, and is 

 the entrance to an alimentary canal, that, descending in the body, 

 swells out into a stomach, and then bends to gain an upward course, 

 having its termination exterior to and underneath the indenture in 

 the tentacular circle. " The lower portion of the stomach is of a 

 bright brown colour, longitudinally striated. The colour appears 

 to depend upon the alimentary materials which it contains, and the 

 vertical strise are probably produced by folds in the organ. On 

 lacerating the stomach, the brown matter escapes in the form of in" 

 numerable minute granules. A sort of vermicular motion is some- 

 times observed in the stomach." 



The ova are generated in that portion of the polype-tubes which 

 is prolonged from the stomach through the common mass (fig. 2), 

 not germinating in any certain point, but from all the gelatinous 

 sides. " Those which are perfectly matured are of a dark reddish- 

 broAvn colour. Others of the same size have their external envelope 

 opake and white; others are somewhat smaller and translucent, 

 whilst some are very minute and perfectly transparent. The mature 

 and immature ova appear scattered indiscriminately throughout the 

 tube. The ova are stated by Raspail to occur in a double series ; I 

 have, however, almost invariably found them in a single row. M. 

 Ptaspail also says he has been able to see the small filament which 



connects the ova to their containing membranous tube." There 



appears to be no duct or aperture through w^hich the ova can escape, 

 their liberation being apparently dependent on the decomposition of 

 the body. This is of two kinds : " In the first, the papilla, which 

 during life closes the tube, dies and becomes softened, ragged, and 

 flocculent, and in this state no longer forms a barrier to the exit of 

 the ova. In November, many of the specimens were seen in this 

 condition. On examining the surface of the polypiferous masses, 

 they were seen covered with ragged shreds of membrane, instead of 

 the well-defined conical papilla3 or expanded polypes. In the second 

 stage, air is disengaged from decomposition of the contents of the 

 horny tube or ovary. If a recently dead specimen, in which the 

 papillae are reduced to the state above described, be examined with 

 the lens, a succession of air-bubbles are seen frequently escaping 

 from the horny tubes. By the successive formation and ascent of 



