11 



however, appears to me, I confess, doubtful; and I am rather inclined to 

 believe that near the place where the young Polypi appear to push forth, the. 

 aperture of the ovary exists, from which the minute ovum having escaped, and 

 by means of its gluten adhering to the parent, thus forms a sort of placenta 

 from which the extruded animal draws for a period its vital sustenance. I sus- 

 pect that I have detected the aperture or apertures of the ovaries in APIO- 

 CRIMTES ROTUNDUS, between the angles near the adhesion of the joints of the 

 pelvis and costse, as also in the division,of INAUTICULATA between the scapula. 



Whether the Crinoidea did or did not possess a vent, still remains doubtful. 

 Their organization appears to have been such as might, perhaps, have enabled 

 them to dispense with this part; since the sphincter muscle at the bottom of 

 the stomach (the apex of the column) permitted, probably, only those juices to 

 pass into the alimentary canal which were destined to be assimilated into the 

 system, and matter, not so applicable, may easily have been disgorged by the 

 mouth. Even the juices carried into the alimentary canal, too abundant for 

 the general recrements needed by the animal frame, may have been exuded 

 through vessels between the joints, and have been employed in repairing occa- 

 sional injuries, or forming additional lamina to strengthen the fabric. 



The liability to frequent accidents to which animals formed of such numer- 

 ous parts as the Crinoidea must be exposed, renders their having a power of 

 repairing injuries sustained, and of reproducing portions lost, necessary ; and 

 that they have this is verified, beyond doubt, by the specimen of PENTACRINUS 

 CAPUT MEDUS.E, recently in the possession of the late Jotia-Tobin, Esq. 



The mode in which the numerous ossicular concretions of these animals are 

 connected together by a gelatinous muscular substance only, renders their 

 separation after death easily accounted for, and explains the rare occurrence 

 of perfect specimens in a fossil state. The formation of all the ossicula by cal- 

 carious secretions, furnishes the reason why they have been so perfectly pre- 

 served in the mineral strata, although changed into foliated spar similar to that 

 which generally occurs in the remains of Echini and Asteria. 



Where the muscle is preserved, or a portion of the animal oil, however 

 minute, intervenes between the fossil and the imbedding substance, or between 

 two joints, they easily separate, and if exposed to the gradual action of au 

 acid, not unfrequently muscular fibre itself may be developed. 



