PEOGRESS OF MICROSCOPICAL SCIENCE. 135 



except in the fact of the striation. In both the nuclei were irregu- 

 larly distributed. The appearance of the striated fibre reminded one 

 of a string of rhombic heads, which bore no relation to the position of 

 the true nuclei. The striated fibres appeared, after a careful dissec- 

 tion of the parts in a number of specimens, to be the retractors of the 

 radula ; they were longer and in narrower bands than the non-striated 

 fibres, and compai*atively much fewer in number. The striation was 

 most evident towards the middle of the fibres, and became evanescent 

 towards their extremities. 



Are the BracMopods Annelids f — Mr. Edward S. Morse replies at 

 some length to the views of Mr. Wm. H. Dall on the above subject, 

 and as his remarks extend to some length, but are of great interest, 

 we give them bodily to oiu* readers. " Mr. Dall says that the ' utmost 

 impartiality ' should be used in the discussion, and ' due consideration 

 should be given to the facts,' &c. This ' utmost impartiality ' is 

 illustrated, by passing over in absolute silence, not only all my refer- 

 ences to the limited knowledge we possess of the embryology of the 

 Brachiopods as shown by Lacaze-Duthiers, but the dorsal and ventral 

 plates — the serial arrangement above and below of setae, and even the 

 gill laminae in Lingula, as first recognized by Savigny in the Annelids 

 — the bi-lobed lophophore — the cej)halic collar — the thin and mus- 

 cular visceral walls — the singular results obtained by Gratiolet in 

 the chemical analysis of the shell of Lingula anatina — the presence of 

 the caecal prolongations of the mantle, and their relations to the paren- 

 Jcanale in the Annelids — and, above all, the remarkable existence of 

 one or more pairs of segmental organs, in form, character, and functions 

 like the segmental organs of the Annelids, the first feature that led 

 me to regard the Brachiopods as Annelids six months before I ever 

 saw living Lingulce. All these points are passed over in the ' utmost 

 impartiality ' of silence. Overlooking with the same impartiality my 

 statement that the Brachiopods presented a compreliensive type, and 

 comprised certain crustacean characters, he neglects to mention the 

 winter egg of the Polyzoa, and similar features in the lower Crustacea, 

 and we might add similar features in certain Eotifers, now admitted to 

 be worms. So also the presence of striated muscular fibre in certain 

 muscles of the Brachiopoda, their absence in the Mollusca (?), and 

 their presence as one of the prominent characters in Crustacea. He 

 gives us, however, Clark's definition of the Mollusca, which comprise 

 the characters of the branch as then understood, which includes, of 

 course, the Tunicata, Polyzoa, and Brachiopoda. In defining the 

 Vermes, with the same impartiality, reference is made only to those 

 Vermes in which the body is made up of a repetition of similar parts, 

 overlooking entirely the unsegmental Vermes which comprise a large 

 proportion of the class ; nor is reference made to the remarkable 

 cephalization of many Annelids, where the posterior portion of the 

 body has been called a caudal appendage, being without bristles. In 

 some, the thoracic rings, few in number, have a wide flaring mem- 

 brane running continuously along each side (Protula). We leave others 

 to judge of his conclusions respecting the character of the setae, as 

 also his startling homology of the pedimcle of Lingula, and the 

 VOL. V. L 



