. Catalogue of the Chaetopoda in the British Museum (Natural History). Oligochaeta; Polychaeta. Fig. 48.—, from California. Anterior end, dorsal aspect; show- ing the large and folded lateral lobes of the A^-„ Fig. 49.—-4. pusilla, from Atka Island. Anterior aspect, showing the prostomimn (PR.), with its large lateral lobes, the nuchal groove (), and the mouth (Mo.). a full, convex curvature,^ and is proportionally larger than in any other species; five pairs of nephridia, which open on the fifth ^ to the ninth segments; several (four to sixteen) pairs of oesop
. Catalogue of the Chaetopoda in the British Museum (Natural History). Oligochaeta; Polychaeta. Fig. 48.—, from California. Anterior end, dorsal aspect; show- ing the large and folded lateral lobes of the A^-„ Fig. 49.—-4. pusilla, from Atka Island. Anterior aspect, showing the prostomimn (PR.), with its large lateral lobes, the nuchal groove (), and the mouth (Mo.). a full, convex curvature,^ and is proportionally larger than in any other species; five pairs of nephridia, which open on the fifth ^ to the ninth segments; several (four to sixteen) pairs of oesophageal glands, the anterior fairly long and slender, the others shorter and more or less pear-shaped ; septal pouches absent; statocysts absent. HisTOKiCAL Account and Remaeks on the Type — The species Arenicola pusilla was founded by Quatrefages on a single incomplete specimen from Coquimbo, Chile. The diagnosis—" Annuli ebranchiati 9. Branchiae magnae ramosissimae "—the only infor- mation given, was inadequate, and the position of this with regard to other species of the genus was indeterminable until the writer (1910) examined the type specimen. Claparede (p. 301) seems to have suspected that Neapolitan examples of "A. marina" miglit be specifically distinct from North Sea specimens. He noted that the former were much smaller and that their gills were not bushy; but it is remarkable that, while studying the blood-vessels and nephridia, he did not observe and ^ This character is especially clear in specimens not more than about 100 mm. in length, * Rarely is a nephridium present opening on the fourth Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ashworth, James Hartley, 1874-1936; Ashworth, James Hartley. London, Printed by Order of the Trustees of the
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