204 
THE VOYAGE OF H.M.S. CHALLENGER. 
individual was developed between the penultimate and the last segment. In our own. 
country it is one of the most remarkable sights in the group to observe the parent-stock 
of this form moving gracefully about with a long string of buds at its posterior extremity. 
Frey and Leuckart^ extended the history of the subject by a careful examination of 
Syllis prolifera from the North Sea. They observed in the line between two segments 
a new process which forms an interpolated segment, and this, as a real bud of the 
anterior moiety of the animal, is developed after the manner of such structures, and by 
degrees is separated as a complete individual. From these observations, indeed, and his 
own on Nais p)roboscidea, Max Schultze concluded that the former was a clear case of 
fissiparous development, whereas in the latter a division takes place. Greeff ^ also gave 
an account of the usual budding in Autolytus from Heligoland. Frey and 
Leuckart did not find the generative products fully develoj)ed in their examples of the 
buds ; but Krohn ^ made further observations a few years later, though he did not quite 
complete the history. The latter was accomplished by Alex. Agassiz,^ who, in Autolytus 
cornutus, described the parent-stock, and traced from the elements of the male and 
female buds the growth of the young embryo into a parent-stock. A similar but not 
identical mode of development occurs in the British ProcercBct picta. In Filigrana, a 
genus of the Serpulidm, Sars,® Oscar Schmidt ® and Huxley ’’ have shown that linear buds 
are developed posteriorly. 
So far as the foregoing observations go, the specimens exhibited only linear budding, 
but in 1863 Alex. Pagenstecher ? described what he termed lateral budding in 
gemmifera, from the Port of Cette. This, however, as Fillers has pointed out, is only a 
further development of the condition formerly shown by CErsted in his Exogone naidina, 
or as very early indicated by Martin Slabber. Nothing approaching to a lateral bud exists. 
As stated in 1868,® Vaillant’s^® supposed new instance of reproduction by budding is 
due to a misapprehension. The so-called buds appear to be the tentacles (furnished with 
pigment-spots at the tip) of a Poly cirrus or closely allied form. With this view Ehlers" 
coincides. 
Fissiparity similar to that in the Syllidians previously mentioned has occasionally 
been observed in other groups, as in the Eulcdia gracilis of Verrill.^® In this, one of 
the segments is larger than the rest, and develops a distinct pair of eyes. Langerhans, 
in one of his interesting papers on the Annelids of the Canaries,^® describes an instance, 
1 Beitrage zur k. wirbell. TMere, &c., 1847, p. 91. ^ Archivf. Naturgesch., 1866, p. 352. 
^ Archivf. Paturgesch., 1852, p. 66. ^ Journ. Boston Soc. Nat. Hist., vol. vii. p. 392. 
5 Fauna litt. Norvegise, p. 86. 
Neue Beitrage zur Naturgesch. d. Wiirmer, Jena, 1848, p. 33. 
’’ Edin. New Phil, /owm., January 1855, p. 113. ® Zeitschr.f. wiss. Zool., Bd. xii. p. 267, Taf. xxv., &c. 
8 Trans. Roy. Soc. Edin., vol. xxv. p. 309. 
1° Ann. d. Sci. Nat. (Zook), ser. 5, 1865, p. 243, pi. iii. Op. cit., ii. p. 15. 
Report of U.S. Commissioners of Fish and Fisheries, &c., 1873, p. 586. 
13 Nova Acta Acad. Gees. Leop., &c., Bd. xlii.. No. 3, Halle, 1881, pp. 95-105. 
