14 ANNALS NEW YORE ACADEMY OF SCIENCES 



IV. Ontogenetic Description of Species 



A. RECENT species 



1. Cerithium tuberosum Group 



a. European Species 

 Cerithium tuberosum Columnce 

 Plate I ; plate ii, fig. 4 ; plate iii, fig. 4 ; plate iv, fig. 1 ; plate vi, figs. 1, 3. 



1616. Cerithium [Buccinum] tuberosum Fabii Columns, De aquatilibus. pp. 



53, 57. 

 1843. Cerithiwni. erythroronense Lamarck. Animaux sans vertebres, ed. 2, IX, 



292. 

 1855. Cerithium tuberosum Sowerby, Thesaurus Conch., II, 855, pi. 178, fig. 49. 

 1866. Cerithium tuberosum Reeve, Conch. Iconica, XV, pi. 1, fig. 5, No. 5. 

 1898. Cerithium erythrwonense Kobelt, Syst. Conch.-Cabinet von Martini u. 



Chemnitz, Bd. I, Abth. 26, 78, pi. 15, figs. 2, 3. 

 1887. Cerithium erythrwonense Tryon, Manual of Conch., IX, 123, pi. 20, fig. 16. 

 1906. Cerithium erythrwonense Cossmann, Essais de Pal6oconch., VII, 67. 



The original description by Fabii Cohimm-e is given under tlie discus- 

 sion of the genus. 



Measurements : Length, 64 mm. ; greatest diameter. 29 mm. ; apical angle, 

 34°, changing on the 9th volution to 29.5° ; sutural angle, 91°. 

 Color : Pale brown or brownish yellow. 



The protoconch is not preserved on any of the specimens obtainable. 

 The first volution retained is .7 mm. in diameter, and this corresponds 

 in size with the first volution beyond the protoconch of Cerithium adan- 

 soni. The surface features are entirely obliterated on this volution, but 

 the next shows traces of the ornamentation, which is apparently the same 

 as that of C. adansoni at the same age. The fourth volution has two 

 strong spirals, the upper of which defines the shoulder, with one spiral 

 intercalated between them. There are also four equal spirals above and 

 two below the primary ones. All the spirals are crossed by ribs, of which 

 there are nine on this volution. On the succeeding volutions more 

 spirals are added on the shoulder and the lower slope of the whorls, and 

 their number is also increased by intercalation between those already ex- 

 isting. At about the eighth volution the spirals become much crowded, 

 and are raised into a strong ridge just below the suture. The same type 

 of ornamentation persists for eleven volutions, but on the twelfth the 

 lower of the two equal spirals becomes weaker, and the outline of the 



