8 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 39. 



oesophageal glands, as in A. marina, this specimen has five pairs, the 

 first being 9 to 10 mm. long and the others 1.5 to 3.5 mm. long. 

 There are no muscular pouches on the first diaphragm (these struc- 

 tures are present in A. marina), and statocysts could not be found 

 after careful search.*^ Five pairs of nephridia are present, opening 

 on the fifth to the ninth segments. These internal characters and 

 the nature of the prostomium indicate that the worm is to be referred 

 to the species A. claparedii Levinsen. Child's record of A. marinxi 

 from Puget Sound is founded on a misapprehension. He was con- 

 cerned with the cytology of the ova and probably did not make any 

 examination of the systematic characters of the worms. Johnson* 

 states that the specimens examined and recorded by him as A. 

 claparedii were given to him by Child; moreover, subsequent records 

 of specimens from Puget Sound and all the specimens from that area 

 which I have myself examined belong to the species A. claparedii. 

 We need therefore have no hesitation in transferring Child's record 

 from A. marina to A. claparedii. 



Schmarda records A. piscatorum from the Bay of Paita, but a 

 statement in his description shows that he was not dealing with this 

 species, for he mentions the presence of twenty glandular sacs just 

 anterior to the stomach, that is, the specimen had twenty oesophageal 

 glands, whereas A. marina has only two. I have tried to find 

 Schmarda's specimens, but have failed to do so. Prof. Dr. K. Grobben 

 has been good enough to look through the catalogue of the collection 

 in the Zoological Institute of Vienna, where I thought the specimens 

 might possibly be, but there is no example of Arenicola in that col- 

 lection from the Bay of Paita and no specimen of this genus collected 

 by Schmarda. His specimens from Paita were examples either of 

 A. claparedii or A. assimilis, probably the former, judging from the 

 distribution of these species (see p. 17 and p. 20). At any rate 

 they can not be examples of A. marinxi, as is definitely shown by the 

 number of their oesophageal glands, and we may provisionally regard 

 them as belonging to the species A. claparedii.*" 



a In order to definitely establish the absence of statocysts, it would be necessary 

 to cut serial sections of the anterior end of the worm, but this was impossible in the 

 present instance. 



6H. P. Johnson, Proc. Boston Soc. Nat. Hist., vol. 29, 1901, p. 422. 



c It should be borne in mind that, at the period when the records by Schmarda 

 (1861) and Grube (1859) were published, A . marina, or, as it was then almost universally 

 called, A. 'piscatorum, was the only known caudate species of Arenicola with nineteen 

 segments and thirteen pairs of gills. It was not until 1883 that Levinsen pointed out 

 the characters which distinguish A. claparedii from A. marina. It is easy to under- 

 stand that up to that time all specimens of Arenicola with nineteen segments and 

 thirteen pairs of gills would be at once referred to the species A. marina, a practice 

 which prevailed, with one or two exceptions, until little over ten years ago. 



