324 
DEVONIAN EAUNA. 
every case gone, and possibly if it had been preserved the umbiUcus might have 
been found to have become more closed with age from the thickening of its sides, 
as is clearly the case with many of the figured specimens of de Ferussac's shell. 
Moreover in the British Museum are some specimens of the foreign shell which 
accurately agree with the Devonshire fossils in the size of their umbilicus as well as 
in other points. It appears, therefore, that, at least until better evidence is forth- 
coming, Phillips must be regarded as correct in identifying our Devonshire 
species with the B. striatus of de Perussac or Bronn. 
De Perussac appears to have only catalogued his shell in 1826, without 
describing it; but d'Orbigny gives an elaborate description of it accompanied by 
many beautiful figures in de Perussac and d'Orbigny's ' History of Cephalopods ' 
(published 1835 — 48) ; and as these two authors worked in common this descrip- 
tion may be regarded as authentic. He there shows that in its young state it is 
identical with B. lineatiis, Goldfuss MS. ; that in its median state it agrees with 
B. striatus as originally defined ; and that in its aged state the striae become 
flounced, and then it is identical with B. undulatus, Goldfuss MS. He gives 
figures of all these stages and of some intermediate forms. Of the old or flounced 
stage I have not as yet seen any British example. D'Orbigny doubtfully refers 
the species to the shell figured in 1781 by Von Hiipsch. 
Bronn's B. striatus is evidently the same species as de Perussac's, whom, 
however, he does not quote before the third edition of his Lethaea. His figures 
show that the umbilicus varied in size, and is sometimes quite as large as are 
those of the English specimens. 
A further question arises as to the name which the species ought to bear. 
De Perussac merely catalogued it without description in 1826. Two years after (in 
1828) Pleming^ described a very difierent and spirally striated shell under the same 
name ; while a third shell is named B. striatus by Sowerby in 1836. Hence it appears 
that Fleming's species has the prior right to the name B. striatus, and consequently 
it is necessary to follow Sandberger and adopt Goldfuss' name for the present 
form, especially as it was given by d'Orbigny as a synonym as early as 1840. 
It only remains to state that authors seem to have been in much doubt whether 
Bronn or de Perussac should be credited with the name B. striatus ; thus Phillips, 
Sandberger, P. A. Romer, and Morris ascribe it to Bronn ; and d'Orbigny, Bronn 
(' Index Pal.,' and ' Lethaea,' ed. 3), P. Romer, and d'Archiac and de Verneuil 
ascribe it to de Perussac. 
Semenow and Moller^ figure as B. striatus, de Perussac, a shell with a much 
more flattened back and a closed umbilicus. 
B. Peloj)s, Hall, which in Dr. Hall's opinion is the same as B.propinquus, Meek, 
1 1828, Fleming, ' Brit. Anim.,' p. 338. 
2 1863, Semeuow and Moller, ' Uber Dev. Schicht. Mittl. Eusslands,' p. 676, pi. iv, figs. 2 a — c, 3. 
