NO. 1772. ANNELIDS OF THE ARENICOLID/E—ASHWORTII. 25 



writers® have considered A. glacialis to be a synonym of A. cris- 

 tata. A^on Marenzeller,^ however, places it under A. marina. 



The specimens, which are in tlie collection of the Smithsonian 

 Institution, are now in a very fragile condition; only one of them 

 is complete, another is in two parts, held together by a strand of 

 muscle, and the other three are fragmentary. I have made as 

 complete an examination of these worms as is possible in their 

 present condition, and having regard to their value as types. The 

 inspection of the internal organs was made on one of the imperfect 

 examples (No. 3 in the list below), which consists of the anterior 

 end as far back as the seventh chsetigerous annulus and was almost 

 dropping to pieces. 



The examination of the specimens shows that A. glacialis is a 

 distinct and valid species. As Murdoch's description is totally inad- 

 equate, I propose to give an account of the species as far as I have 

 been able to investigate it on the material at my disposal. 



The material consists of: 



1. A complete specimen 90 mm, long, of which the tail, which is 

 strongly contracted, forms 11 mm. 



2. A specimen 105 mm. long, of which the tail forms 45 mm. This 

 specimen is broken, about the ninth segment, into two pieces, held 

 together by a strand of muscle. 



3. A portion of an anterior region, 26 mm. long, as far back as the 

 seventh chsetigerous annulus. 



4. A portion of an anterior region, 14 mm. long, as far back as the 

 third chsBtigerous annulus. 



5. A fragment similar to No. 4, 12 mm. long. 



6. A posterior region, consisting of eleven segments and tail, be- 

 longing to either No. 4 or No. 5. 



7. A posterior region, consisting of eight segments and tail. 



8. A branchial region. 



9. A portion of a tail. 



All the specimens are dark brown to nearly black in color. 



Each of the specimens. No. 1 and No. 2, possesses seventeen chss- 

 tigerous segments, the last eleven of which are provided with gills. 

 It is evident, from an examination of all the specimens, that the 

 gills of this species are small. The axes of the largest gills are not 

 more than 2 mm. in length, measured from their origins to the tips 

 of their terminal gill filaments. The first gill may be very small, as 

 in specimen No. 2, and the last gill is smaller than the preceding ones. 



a P. Fauvel, Mem. Soc. Nation. Sci. Nat. Math. Cherbourg, vol. 31, 1899, pp. 1G9, 

 171. F. W. Gamble and J. H. Ashworth, Quart. Journ. Micr. Sci., vol. 43, 1900, 

 p. 428. 



&Zool. Jahrb. Abth. Syst., vol. 3, 1888, p. 15. 



