196 GIBBULA. 



Tungebevsebningen hos de Norske rhipidoglossa. Eurytrochus 

 FISCHER, Icon. Coquilles Vivantes, Trochus, p. 417 (1880). 

 Calliotroehus FISCHER, 1. c., p. 418. 



Gibbula (Leach mss.) Risso, is preceded by Phorcus Risso. The 

 latter name has been used by A. Adams and writers on the shells of 

 West America for the umbilicated Chlorostoma; but such use is of 

 course inadmissible. The name Gibbula has been so uniformly 

 selected by authors in preference to Phorcus that it would be in- 

 advisable to insist on the priority of one page which the latter name 

 has. The subdivisions of the restricted subgenus Gibbula are given 

 on the following page. It will be noted that one author had added 

 no less than seven synonyms to the homogeneous group inhabiting 

 the seas of Europe. Such heaping up of names for groups without 

 characters is highly undesirable. The time is at hand when such 

 performances will bring their authors the discredit they merit. 



The species of Gibbula are very numerous, and are nearly all 

 littoral or laminarian in station. The group is distributed through 

 all seas except upon the coasts of the Americas, which have not a 

 single species. 



The dentition of G. declivis is figured on PL 50, fig. 6 ; G. tumida, 

 pi. 50, fig. 16. Both rhachidian and lateral teeth have well devel- 

 oped denticulate cusps ; the body of the tooth has expanded lateral 

 supporting-wings, and is narrowed toward the cusp. The outer 

 laterals are wider. Radulse of species of Gibbula have been figured 

 by Troschel, Friele, Sars and Hutton. 



Subgenus GIBBULA, restricted. 



This division comprises most of the species. Owing to the fact 

 that there are many forms which I have not seen, and on account 

 of the intergradation of the various types of form, I have not at- 

 tempted to distribute the species into their natural groups or sec- 

 tions, but have simply grouped the forms around certain types of 

 shell-structure, which may be briefly indicated here, this analysis 

 to replace the partial division given on page 12 of this volume. 



Section I. GIBBULA s. sir. (including Forskalia Ads., Magulus 

 Monts., Colliculus Monts., Glomidus Monts., Pudeolu* Monts., Phor- 

 culm Monts., Tumulus Monts., Phorcus Risso, Gibbulastra Monts., 

 Steromphalus (Leach) Gray, Korenia Friele and a number of other 

 names). Shell nodulus or more or less tumid beneath the sutures; 

 generally not much higher than broad, conical, umbilicate (rarely 



