310 GENERAL SUMMARY TO 



attention to the study of the Bryozoa, in her article "Brachiopoda and Bryozoa " in ' Cassell's 

 Natural History/ vol. v, p. 280, 1881, says: "It is evident, therefore, from embry- 

 ological development and adult organisation that the Brachiopoda and the Bryozoa are 

 so closely allied as to form a very natural group, and thus they are classed by the majority 

 of authors. With regard, however, to the exact position in the animal kingdom to be 

 occupied by the group thus restricted, opinions are far less unanimous ; for it is also 

 certain that in the earliest stages of growth the Brachiopoda and the Bryozoa betray no 

 molluscan characters. In fact they present such close resemblances to similar stages of 

 some Worms that such embryological authors as Steenstrup, Morse, Kowalevsky, and 

 Agassiz deny their right to admission to the molluscan type. Prof. Morse deduced the 

 same conclusion from observations of the habits and structure of full-grown Lingula ; 

 but other Zoologists consider these structural affinities merely as throwing light on the 

 geological ancestry of both of these coeval types of organisms." 



With respect to the Tunicata, we are reminded by Morse that Kowalevsky, KupfFer, 

 Schultze, and others assign to them a position at the base of the vertebrate series through 

 the affinities of some of their forms to Amphioxus, as well as their singular embryological 

 relations to the Vertebrates. Gratiolet states likewise that the Tunicata are in no way 

 related to the Brachiopoda; and Hancock, in 1870, expressed himself to me by letter as 

 follows : — " Of late years I have gradually inclined to the opinion that the Brachiopoda are 

 not so closely related to the Tunicata as we at one time thought. I am busily engaged in 

 working out the Tunicata, and they seem to me to be very intimately connected with the 

 Lamellibranchs. I am disposed to consider that there is a considerable hiatus dividing 

 the Tunicata from the Brachiopoda and the Polyzoa or Bryozoa, and that the latter two 

 groups should be included in the Molluscoidea. If, therefore, Morse can establish his 

 doctrine, it will relieve me of some little difficulty, inasmuch as it will militate against 

 Huxley's view that the branchial sac of the Ascidian is the homologue of the pharynx of 

 the Polyzoa ; my idea being that the branchial sac is the true representative of the gill- 

 plaits of the Lamellibranch, and has nothing to do with the pharynx of the Polyzoon. 

 There are some characters of the Brachiopoda that are very puzzling." 



It is therefore evident that the dismemberment of the Molluscoidea must be considered 

 necessary, and that, at any rate, we cannot place the Brachiopoda and the Polyzoa in 

 the same division with the Tunicata. 



The Brachiopoda have been considered by Gratiolet and some others as allied to 

 the Crustacea in respect of their vascular system, and not to the Mollusca nor to the 

 Tunicata. 



Prof. Morse reminds us also that thirty-five years ago Prof. J. Steenstrup had not only 

 recognised the Brachiopoda as worms, but had placed them near the tubicolar Annelida. 1 



Lacaze-Duthiers separates them from the Acephala mainly on account of their 



1 "Om Anomias stilling til Meislingerne og Terebratulerne " ' Skandinavian Naturf. Forhandl.,' 1847 

 (' Proc. of the Royal Danish Academy'). 



