80 BULLETIN 90, UNITED STATES NATIONAL MUSEUM. 



Vitreolina Monterosato, Nom. Conch. Medit., 1884, p. 100. Type, E. dis- 



iorta Jeffreys, not Desliayes. (Section of Eulima.) 

 Aciculai-ia Monterosato, Nom. Conch. Medit., 1884, p. 102. Type, Exilima 



herylUna Monterosato. (Section of Eulima.) Not Acicularia Adams, 



1875. 

 Subularia Monterosato, Nom. Conch. Medit., 1884, p. 103. New name for 



Liostraca H. and A. Adams. 

 Haliella Monterosato, Bol. Malac. Ital., 1880, p. 74. Type, Eulima stenos- 



toma Jeffreys. Not Halliella Ulrich, 1891. 

 Melanella and Eulima Dall, Bull, Mus. Comp. Zool., vol. 18. 1889, p. 326. 



Melanella proposed by Bowdich four years earlier than Eulima 

 should, as pointed out by Fischer in 1887, be accepted as the generic 

 name of this genus as originally conceived. However, in dividing 

 the genus into groups, it is still possible to retain the familiar name 

 of Eulima^ as indicated by me. The researches of my colleague, Dr. 

 Paul Bartsch, have shown that the groups in this genus are difficult 

 to separate sharply by the shell ; the absence of characters except of 

 the most simple kind is, one may say, characteristic of the shells of 

 the genus. 



The anatomical relations are hardly more satisfactory. Since 

 these animals are found even at great depths, as well as between 

 tides, and comprise both free-living species and those which are com- 

 mensal or even truly parasitic, they are subject especially to the 

 direct action of the environment, including degenerations due to 

 disuse of organs. 



Rosen has found Eulima polita, a large free species, to be pos- 

 sessed of a radula " mit zahlreichen Zahnen." This species also has 

 eyes situated behind the tentacles, and a well developed operculum. 

 Eulima distorta^ however, a parasitic species, is without a radula, 

 living on the juices of its host. The former is opaque and (for the 

 genus) heavy; the latter, as its situs requires, is smaller, pellucid, 

 and thin. It is well Imown that deep-sea shells lose weight and 

 color, and frequently their optical organs; Eulima stenostoma Jef- 

 freys lives in 75 to 410 fathoms, and has the aspect of shallow-water 

 species, which bear color markings. It is, however, colorless and 

 blind. The peculiar tortuosity of the spire characteristic of typical 

 Melanella is found in all degrees of emphasis, some specimens of the 

 same species being absolutely straight axially and others more or 

 less tortuous, contrary to the opinion I had formed from insufficient 

 material in 1889. It is, therefore, evident that this character can 

 not be used to divide groups. The acuteness of the apex varies in 

 different species, and the position of the varices, with relation to 

 each other, in the same species is not constant ; nor, Doctor Bartsch 

 assures me, does the presence of internal projections due to the 



