No. 2.] THE M ESQ BLAST-BANDS IN ANNELIDS. 219 



While the foregoing article was in process of publication I received R. S. 

 Bergh's full paper on the germ-bands of Lumbricus \Zeitschr. f. wiss. Zool., 

 L. 3, 1890]. This admirable worlv contains a complete confirmation of my 

 discovery of the teloblasts and cell-rows of the middle stratum of the germ- 

 bands in Oligochasta — a confirmation which has especial significance on 

 ■account of the curiously exaggerated and, to me, quite inexplicable, hostility 

 with which its author saw fit to receive the original announcement of that 

 discovery. Dr. Bergh's paper, as a matter of course, exhibits in some degree 

 the well-known and characteristic skill of its author in belittling the work of 

 other investigators, but I observe with interest many signs of progress, both 

 in knowledge of the germ-bands and in acquaintance with the usual forms of 

 courtesy in scientific discussion. The author, for instance, no longer seeks to 

 discredit my work by innuendoes directed against my scientific good faith ; 

 indeed, the existence of the teloblasts and cell-rows has even become " sehr 

 leicht zu konstatiren " — an evidence of progress on which I congratulate 

 my learned and courteous critic. It is not improbable that Dr. Bergh may 

 in time be able to observe with equal ease the teloblasts and other structures 

 I have described in Nereis. 



Apart from the development of the glandular portions of the nephridia, my 

 general account of the structure, mode of growth, and relations of the various 

 parts of the germ-bands in Litmbriais is confirmed in every respect. He 

 adds, however, the very interesting discovery that the products of the neuro- 

 blasts are reinforced by a median nerve-plexus that is taken up into the 

 ventral nerve-chain between the two neural cords. His account of the 

 " nephroblasts " and "lateral teloblasts " differs entirely from that given by 

 Whitman and myself. Their connection with the nephridia is denied, and 

 they are asserted to be " myoblasts" which give rise to the circular muscles. 

 This result, if well founded, is of the greatest interest, and marks an im- 

 portant advance in our knowledge of annelid embryology. It is to be hoped, 

 however, that the question may be carefully re-examined, by some fair-minded 

 observer, in Clepsine or some other favorable form. 



Bryn Mawr, Pa. 



