Miscellaneous. 93 



has added a few observations on the (earlier embryonic stages of 

 Esclisclioltziay Beroe, and Eucharis, completing deficiencies in his 

 earlier papers on the enibryologj- of Ctenophora. These supple- 

 mentary observations agree completely with the observations of 

 A. Agassiz on the embrj-ology of Ctenophora. 



The second memoir is a vorj' complete history of the development 

 of Krachiopods, strikingly in accordance with the views of Stecnstnip 

 and of Morse on the affinities of Brachiopods with Annelids. Tho 

 homology between the early embryonic stages of Arr/iope and well- 

 known Annelid larvae is most remarkable ; and the resemblance 

 between some of the stages of Arr/lope figured by Kowalevsky and 

 the corresponding stages of growth of the so-called Loven type of 

 development among Annelids is complete. The number of segments 

 is less ; but otherwise the main structural features show a closeness 

 of agreement which will make it difficult for conchologists hereafter 

 to claim Brachiopods as their special property. The identity in 

 the ulterior mode of growth between the embryo of Argiope and of 

 Balanoylossus in the Tb/viamt-stage is still more striking : we can 

 follow the changes undergone by Arci'iope while it passes through its 

 7'oj-nffria -stage (if we may so call it) and becomes gradually, by a 

 mere modification of the topogra])hy of its organs, transformed into 

 a minute pedunculated Brachiopod differing as far from the Toniaria- 

 stage of Anfiojje as the young B({hino(/lossus differs from the free- 

 swimming Tomaria. In fact, the whole development of Argiojie is 

 a remarkable combination of the Loven and of the Tomaria types of 

 development among Worms. His paper also includes the history of 

 a less vermiform type of development, that of TliecifJium and of 

 Terehratuhi, in which the observations of Kowalevsky fullj- agree 

 with the previous well-known memoir of Lacaze-Dutbiers on 

 Thecidium, and of Morse on Tenhratulina. It is not out of place 

 to recall the very ungenerous treatment which Morse received at 

 the hands of many conchologists for the heresies of his papers on 

 the systematic position of Brachiopoda ; and it certainly is a 

 striking proof of the sagacity of Morse, to have announced so posi- 

 tively, from the history of the American Brachiopods alone, tho 

 vermiform affinities of Brachiopods, now so conclusively proved by 

 the development of Arr/iope in Kowalevsky's paper. 



The close relationship between Brachiopods and Bryozoa cannot 

 be more fully demonstrated than by the beautiful drawings on 

 pi. v. of Kowalevsky's history of Thecidium. We shall now have 

 at least a rational explanation of the homologies of Brachiopods, 

 and the transition from such types as Pedicellina to Memhrani- 

 pora and other incnisting Bryozoa is readily explained from the 

 embryology of Thecidium. In fact, all incrusting Bryozoa are only 

 communities of Brachiopods the valves of which are continuous and 

 soldered together, the flat valve forming a united floor, while the 

 convex valve does not cover the ventral valve, but leaves an open- 

 ing more or less ornamented for the extension of the lophophore*. 

 — Sillimans American Journal, Dec. 1S74. 



• Mr. B. P. Mann translated for nie the explanation of the plates of the 



two memoirs of Ko\valev^!:v. 



