THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SECOND SERIES.] 

 No. 113. MAY 1857. 



XXVI. — Researches on the Development of the Pectinibranchiata. 

 By J. KoREN and J). C. Danielssen*. 



[With two Plates.] 



The development of Buccinwn undatum and Purpura lapillus 

 differs so much from anything ah'eady known, that we cannot be 

 astonished that the correctness of our former observations has been 

 doubted. To dissipate these doubts, and remedy the imperfec- 

 tions which occur in our first work, we have thought it necessary 

 to recommence our researches; and now, in publishing the results, 

 we can compare them with the investigations of J.Miillert, Vogt J, 

 Kx'ohn§, Leuckart||, Gegenbaur^, and Carpenter**, on the 

 marine Mollusca, with which science has recently been enriched. 



Buccinum undatum, Linn. 



Tlie capsules which enclose the eggs are connected together, 

 and form round or oval groups, which may attain a consider- 

 able size. They are often attached to different bodies, for ex- 

 ample, to stones, old pieces of wood, oysters, &c. 



* Translated by W. S. Dallas, F.L.S., from the 'Fauna littoralis Nor- 

 vegise,' by M. Sars, J. Koren, and D. C. Danielssen; Bergen, 1856. 



t Ueber Synapta digitata, und iiber die Erzeugung von Schnecken in 

 Holothurien. Berhn, 1852. Transl. Annals, new series, vol. ix. 1852, 

 pp. 22 & 103. Ueber die Entwickelungsforinen einiger niedern Thiere 

 (Berlin Monatsber. 1852, p. 595). 



X Bilder aus dera Thierleben. Frankfurt, 1852, p. 290. 



§ Archiv fiir Naturgeschichte. Berhn, 1853, p. 223. 



II Zoologische Untersuchungen. Giessen, 1854, 3 Heft, ]). 64. 



•[[ Untersuchungen iiber Pteropoden und Heteropoden. Leij)zig, 1855. 

 ** Quarterly Journal of Microscopical Science, 1855, no. xi. p. 17. 

 Ann. ^ Mag, N. Hist. Ser. 3. Fo/.xix. 23 



