125 



For recognizing these as ovarian pores we have the following reasons ; — 

 1. They are situated at the bases of the arms where the ovarian tubes 

 must pass from the grooves into the perivisceral cavity. 2. When com- 

 pared with the ovarian pores of a Sea-urchin they have the same size, 

 form and aspect. Fig. 84, represents the ovarian pores of the Sea-urchin 

 Toxopneustes Drohachiensis Ag. natural size and arrangement. It may 

 not appear at first view that this latter comparison has any probative effect. 

 But it has, in this way. If these apertures in (7ar?/ocrm«s were large open- 

 ings a like wide, as are some of the ambulacral orifices of the Crinoids, I 

 would say that they were unlike true ovarian apertures. 



According to the new theory, this Echinoderm Caryocrinus ornatus 

 was a polystome animal, and drew in its food through its six ovarian 

 apertures, the large valvular orifice being the anus. To me this appears 

 to be utterly incredible. 



In fig. 83 I have represented the mouth of Leskia mirabilis Gray. 

 Both Dr. I. E. Gray and Prof. Loven have pronounced this aperture ta 

 have the structure of the valvular orifice of the Cystidea. I have not 

 the slightest doubt whatever but that the mouth of the Cystideans fore- 

 shadows that of the Sea-urchins. There is nothing whatever in its structure 

 to show that it is not the mouth, but on the contrary. 



The new theory is not founded upon any peculiarities in the structure 

 of the ambulacral orifices, which would show that they are oral apertures^ 

 but only upon the four objections above noticed. The first of these is not 

 logical, while at the same time it is purely theoretical, and avails nothing 

 against material and visible facts. The fourth is completely disposed of 

 by Dr. Carpenter' s observations, which prove that in the Crinoidea the 

 arms have no share whatever in the ingestion of food. The second and 

 third objections are the same in substance, i. e., according to the second 

 the supply of water to the mouth is diminished by the occurrence of a 

 Platyceras over it, while, according to the third, the same effect is pro- 

 duced by the small size of the aperture itself in some instances. It does not 

 require much consideration to convince one, that if these two objections arc 

 fatal to my views, they are equally so to the opposite theory. In C. 

 stelliformis for instance, the pores through which we must suppose the 

 ovarian tubes issued from the interior are only large enough to admit of 

 the passage of a fine hair. They are scarcely visible to the naked eye. 

 The tube, under any circumstances, must have filled them almost entirely. 

 If any space at all were left for the passage of a stream of water through 

 the pore by the side of the tube it must have been exceedingly minute. 



When weighed as above, therefore, the evidence gives the following 

 results : — The first and fourth objections avail nothing. The second and 



