14 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 39. 



M.GR. 



Arenicola claparedii has been taken at three other points on the 

 western seaboard of America, but was recorded under other names. 

 To the records given above the following should therefore be added : 



A. marina, Vancouver Island. E. von Marenzeller, Zool. Jahrb. Abth. Syst., 

 vol. 3, 1888, p. 12. 



A. pusilla, Coquimbo, Chile. A. de Quatrefages, Histoire naturelle des An- 

 nel6s, p. 266, Paris, 1865. 



A. marina, Puerto Montt, Chile. E. Ehlers, Festschr K. Ges. Wiss. Gottingen, 

 1901, p. 176. 



I have shown above that a re-examination of one of von Maren- 

 zeller' s specimens from Vancouver Island (see p. 7) and of the two 



specimens recorded by Ehlers from 

 Puerto Montt (see p. 9) clearly 

 proves that they do not belong to 

 the species A. marina, but to A. 

 claparedii. 



The specimen from Coquimbo is 

 the type-specimen of A. pusilla, 

 de Quatrefages, the characters of 

 which were thus defined: "Annuli 

 ebranchiati 9. Branchiae magnsB 

 ramosissimas." These diagnostic 

 Nr.. features are so inadequate that the 

 position of this species with regard 

 to other species of Arenicola has 

 been quite indeterminable, and in- 

 deed it has been impossible to de- 

 cide whether or not this species is 

 a valid one. I have recently made 

 an exhaustive examination of this 

 specimen as far as is possible without damaging its diagnostic fea- 

 tures. It is small, slender, and incomplete, only the anterior region, 

 as far back as the eleventh chsetigerous annulus, being preserved. 

 It is about 35 mm. long and 3 to 3.5 mm. in diameter. The first 

 gill is borne on the eighth segment (not the tenth, as stated by 

 de Quatrefages), but is small. The other gills are larger and tend 

 toward the pinnate type. The first seven neuropodia are feebly 

 developed, those of the succeeding segments are larger, and those of 

 the tenth and eleventh segments form well-developed cushion-like 

 ridges. The setae are very similar to those of Californian examples 

 of A. claparedii. The prostomium is very fully everted, carried for- 

 ward, and, as it were, displayed over the anterior end of the worm so 

 that, in order to obtain a view of its lobes, an antero-ventral v^iew 

 is necessary (fig. 3). The lateral lobes of the prostomium are in the 

 form of two flattened disks, the edges only of which are visible in a 



Fig. 3.— Antero-ventral view of the ante- 

 rior PORTION OF "a. pusilla" QUATREFAGES. 



In this view all the parts, except the 

 prostomium, are seen somewhat fore- 

 shortened. X8. L, lateral lobes of 

 prostomium; M, median lobe; M. Or, 



METASTOMUL groove; J/o, MOUTH; iVij', FIRST 



neuropodium. 



