parts, pharynx e, stomach d_ and intestines c_. The appearance 

 of the mouth opening coincides with the beginning formation 

 of the ciliary strings in the auricularia. At this stage there 

 is some data about the transformation of the Echinus lividus . 



Krohn's other reports on the development of echinoderms 

 briefly designate some representatives of the type68 or 

 species. 69 



Special attention must be given to Krohn's investiga- 

 tions on the development of tunicates. Originally his interest 

 was attracted by Salpa, in which the wonderful phenomenon of 

 the alternation of sexual and asexual generations had already 

 been recognized. This discovery belongs to the poet Adalbert 

 Chamisso (1781 - 1838) . With the Dorpat-born zoologist 

 J. F. Eschscholtz, he traveled around the world on the 

 Russian ship RURICK. Chamisso published the results of his 

 investigations in "On Some Animals of the Linnean Class of 

 Worms, noted during a world tour, performed by Count 

 N. Romanzoff, under the command of Otto von Kotzebue, from 

 1815 to 1818, Part I: On Salpa. "70 



68. A. Krohn, "Bemerkungen uber einige Echinodermenlarven, " 

 ARCH. ANAT., PHYSIOL. (1851), pp. 353 - 357; "Uber 

 die Entwickelung der Seesterne und Holothurien (Brief 1. 

 Mitt. a. d. Herausgeb . ) , " ibid . (1853), pp. 317 - 321; 

 "Beobachtungen iiber Echinodermenlarven (Brief 1. Mitt, 

 a. d. Herausgeb.)," ibid . (1854), pp. 208 - 213; "Uber 

 neuen Entwickelungsmodus der Ophiuren," ibid . (1857), 

 pp. 369 - 375. 



69. A Krohn, "Uber die Entwickelung einer lebendiggebarenden 

 Ophiure (Brief 1. Mitt. a. d. Herausgeb.)," ARCH. ANAT. 

 PHYSIOL. (1851), pp. 338 - 343; "Uber die Larve von 

 Spatangus purpureus (Brief 1. Mitt. a. d. Herausgeb.)," 

 ibid . (1853) , pp. 255 - 259; "Uber die Larve des Echinus 

 brevispinosus ," ibid . (1853), pp. 361 - 364. 



70. DE ANIMALIBUS E CLASSE VERMIUM LINNEANA IN 

 CIRCUMNAVIGATIONE TERRAE AUSPICANTE COMITE 

 N. ROMANZOFF DUCE 0TT0NE DE KOTZEBUE ANNIS 

 1815, 1816, 1817, 1818 PERACTA OBSERVATIS 

 ADELBERTUS DE CHAMISSO, Fasc. primus: DE SALPA 

 (Berlin, 1819) , iv + 24 pp. 



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