44 DR. GWYN JEFFREYS ON THE MOLI.USCA OF THE [Jail. 20, 



Fossil. Pliocene : Lamato in Calabria (Philipjn). 

 Trochus (Solariella) lusitanicus, Fischer. 

 An elegant and exquisitely sculptured shell. 



6. Seguenzia laxa', Jeffreys. (Plate V. figs. A, A a.) 



Shell imjierCect, consisting of scarcely two whorls ; these are 

 cyliudrical and scalarifonn, spirally and regularly striated : mouth 

 nearly detached, squarish ; expanding on the inner or pillar side, 

 and somewhat effuse or spread out at the base : umbilicus narrow 

 aud contracted, bi.t deep. L. (apparently) 0-25, B. 0*2. 



' Porcupine' Exp. 1870 : Atl. St. 16. A fragmentary specimen, 

 but peculiar aud worth noticing. Whether it belongs to the present 

 genus, or even to the same family, may be doubtful. However, a 

 perfect specimen will be probably discovered in future deep-sea 

 expeditions. 



Family XXITI. Xenophorid.e. 



Xenophora crispa, Konig. 



Trochus crispus (Konig), Bronn in Italiens Tertiar-Gebilde, 1831, 

 p. 62. 



'Porcupine' Exp. 1870: Med. St. 40, 41, Rasel Amoush, 58. 



Distribution. G. Gascony {De Folin), Mediterranean (Deshayes), 

 Sardinia and Bona {Tiberi), Tuscanv {Jppelius), W. Africa 

 {v. Martens'), C. Verd I. (' Gazelle ' Exp.), off Sahara («Talisraan' 

 Exp.) ; 47-486 fms. 



Fossil. Pliocene ; throughout Italy. ? Post-tertiary : Rhodes. 



X. mediterranea of Tiberi, and X. commutata of Fischer. I can- 

 not distinguish the living from the fossil form by any valid character. 

 The only ground of such distinction would be that usually the 

 umbilicus is more or less open in the former and more or less closed 

 iu the latter. But of two Tertiary specimens now before me from 

 Castel d'Arquato, for which I am indebted to the kindness of Count 

 Angelo Manzoni, one has the umbilicus open and the other has it 

 closed. Bronn says in his description of Trochus crispus, "Umbilico 

 subvariabili, primum aperto, serius subsemiclauso." In consequence 

 of having in the course of my continued labours for more than 

 half a century examined so many thousand, indeed I might say so 

 many ten thousand, specimens of shells from different parts of the 

 North Atlantic, I may perhaps be more inclined to unite or " lump " 

 than subdivide or *' split " species ; arid if any explanation be ex- 

 pected from me for not having adopted all the species proposed by 

 continental conchologists, whose power of discrimination is fully 

 equ.il, if not superior, to my own, I hope to be excused by them in 

 that spirit which is the bond of all science. My old and much 

 valued friend Dr. Tiberi is entitled to the credit of ha\ing dis- 

 covered or confirmed the discovery of the present species as an 

 inhabitant of the Mediterranean. 



Woodward strangely placed this genus with ISolarium in the 

 Littorina family, and he assigned to it Montfort's n* nn- of Phorus ; 



' Loose. 



