56 AMERICAN JOURNAL 



10. .Relation between the statoblasts of Polyzoa, the ephippia of 

 Daphne, and the winter eggs of Rotifers. 



It is difficult to see the special, value of the external appear- 

 ances of eggs which produce very different animals. Our busi- 

 ness is rather with the contents than with the shells. Eggs are 

 very much alike all the world over, whether they be those of 

 mollusks, salamanders, or fish, birds, or turtles. Moreover, the 

 eggs of many of the Brachiopods, as I have had numerous oppor- 

 tunities of noting, are quite spherical, and differ as much from 

 those of Polyzoa and some other Brachiopods as they do from 

 those of very different animals. 



11. The ,l segmental organs, 1 ' or oviducts of Brachiopods, and 

 their close affinity to the oviducts of worms. 



The segmental organs of worms undoubtedly bear, in some 

 cases, a resemblance in appearance and in function to the ovi- 

 ducts of the Brachiopods. The preceding remarks in regard to 

 these organs in the Annelids may be referred to in this connec- 

 tion. There is also a somewhat similar resemblance to be traced 

 between them and the fallopian tubes of vertebrates. Whether 

 there be any homology between them in either case is another 

 and an undecided question. In structure, however, the Anne- 

 lidan organ is very different from that of the Brachiopods. (Cf. 

 Claparede, Annel. Chretop. Golfe Naples, and Williams, Proc. 

 Roy. Soc. 1. c.) Moreover, they are not peculiar to these two 

 groups, if we may believe Dr. Williams, but may also be found, 

 or their homologues, in the Acalephs and in Synapta. In the 

 Brachiopods, the term "segmental" would be a, misnomer, for, 

 shall we believe that Rlvynchonclla is composed of twice as many 

 "segments" as Terebratula, with, in many respects, an almost 

 identical organization? On the other hand, a vast number of 

 worms are entirely without these organs (Cf. Diesing, Bdellideen, 

 Vienna, 1858, and Van Beneden, Recherches sur la Faune lit. de 

 Belgique, Bruxelles, 1860), which cannot be said to be charac- 

 teristic of even the whole class of Annelida, to say nothing of 

 the other worms. If the Brachiopods are to be Annelidized on 

 this single character, what shall be done with those Annelids 

 which do not possess it? 



The segmented embryo of Thecidium and Dentalium has been 

 already referred to, as well as the fact that Prof. Morse's studies 

 on the embryology of Terebratulina did not discover any segmen- 

 tation in that quarter. The character cannot be considered as 

 of value in any but the most limited sense. 



