326 SERPULIDA. 
MacMunn thought that the blood of Serpula contortwplicata (Hydroides norvegica) 
presented some resemblance to that of Sabella, yet did not contain the same kind of 
chlorocruorin, but a pigment closely related to it, probably nearer hematin. 
Gravier (1902) quotes from Zeleny' an instance of regeneration of an operculum in 
Hydroides dianthus—after its removal by the experimenter. The curious feature about 
this case is that the operculum was not reproduced on its original site, but the rudimentary 
organ of the other branchial edge developed into a complete operculum. 
Soulier® (1878-1902), in memoirs dealing with the development of Serpula infundibulum, 
Hydroides pectinata and Protula Meilhact, came to the conclusion that the blastopore 
formed both the mouth and the anus, the region of the elongated blastopore between them 
corresponding to the ventral surface of the annelid. Later® (1906) the same author gave 
an elaborate account of the fecundation of Serpula. 
Schepotieff* (1903) gives an account of the minute structure and development of the 
bristle-bundles of Protula tubularia (P. intestinwm, Philippi), the basal regions of which he 
in the ccelom. He describes the bristles as developing from special nucleated cells, and 
not from a sac, and in the same way the hooks spring from cells at the bottom of an insinking 
of the epiderm. The so-called bristle-sacs thus do not exist. The same author’ furnishes 
an elaborate account of the structure of Polycheet bristles, referrmg especially to Nereis, 
Aphrodita and Spirographis—showing likewise their origin from cells. 
Wollebk (1912) arranges the northern Serpulide according to the structure of the 
branchie, the nature of the operculum, the number of the anterior (thoracic) segments, and 
the nuchal bristles. . 
Seven species of the family, viz., Sperorbis borealis, S. Fabric, Morch, S. lucidus, Mont., 
Ditrypa libera, Placostegus tridentatus, Protula borealis and Filograna implexa were found 
by M. Sars® at 300 fathoms. Recent investigations have greatly increased the range in depth 
in these and other cases. 
The earlier investigators of the Serpulids gave a large share of their attention to the 
calcareous tubes, founding species on the nature of the coils and their texture, or, it may be, 
on the structure of the opercula and branchie. No modern investigator, however, would 
feel safe in relying on these distinctions without also subjecting the bristles, hooks, body- 
wall and life-history to careful examination. In order to indicate the proportional abundance 
of the Serpulids in British waters, notes of a few of the collections made by exploring ships 
and by zoologists at various limited localities are added, as well as extracts from one or two 
-memoirs devoted to the group. 
Philippi’ (1844) furnished a description of the Mediterranean Serpulids, entering no less 
than twenty-six, though Grube in the same region had only twelve. Philippi relied much 
1 ¢ Archiv fur Entwickl.,’ Bd. xi, 1902. 
2 “Compt. Rend. Acad. Se. Paris,’ t. cxxvi; idem, t. exxvin; and ‘Travaux l'Institut. Zool. 
Univérsité Montpellier,’ Mem. No. 9, 1902, pp. 60, etc., pls. 1—1v. 
3 «Arch. Zool. Expér., 4° sér, v, p. 403, pl. x. | 
4 «Zeitschr. f. wiss. Zool., Bd. lxxvii, p. 586, Taf. xxvi—xxvin, 1904. 
® Thid., Bd. Ixxiv, pp. 1—57, Taf. xxxiii—xxxvi, 1903. 
6 «Vidensk.-Selsk. Forhandl., 1868, pp. 9 and 10 (sep. copy). 
7 «Arch, f. Naturges.,’ Bd. x, p. 186, Taf. vi, figs. a—T. 
