504 G. CO. Crick—Two Type-specimens of Ammonites. 
it is obvious that the date of publication of the species was taken from 
the title-page of vol. i, this bearing the date 1812. But, as is well 
known, the ILneral Conchology was issued in 113 numbers or parts, the 
first sixty-five parts being by James Sowerby, and the rest by his son, 
James de Carle Sowerby. Vol. i included Nos. i—xviii, which appeared 
between 1812' and August, 1815. The figures and description of 
Ammonites cordatus (pp. 51-2, pl. xvii, figs. 2 and 4) were published in 
No. iv, which is dated April 1, 1813, the same date appearing on the 
plate. It is obvious, therefore, that the date of publication of the 
species is not 1812, but 1813. 
Sowerby figured two specimens (figs. 2 and 4), but regarded the 
original of his fig. 2 as the type of his species; for, referring to 
the fossil represented in his fig. 4, he says: ‘‘I am much inclined to 
consider it as a distinct species.” The original of fig. 2 is therefore 
the holotype, and that of fig. 4 a paratype. Respecting the para- 
type Miss Healey states: ‘‘ The difference between the photograph of 
the paratype and the original figure [fig. 4] is striking, but there can 
be no doubt about its identity, as it bears a label on which is written 
in Sowerby’s handwriting (Ammonites cordatus, M.C. 17, fig. 2, 4) 
and the green wafer with which he marked figured specimens.” As 
will be seen from a comparison of Sowerby’s figure of the holotype 
with the photograph of the same given in the Palgontologia universalis, 
Sowerby’s figure is reversed; but it would seem from the figures of 
the paratype given on the same plate of the Palgontologia universalis 
that in this case Sowerby’s figure was not reversed. However, 
a careful examination of the paratype, especially of the septal surface 
at the anterior end of the specimen, shows that Sowerby’s figure, so 
far as the outer whorl is concerned, is reversed; and that the inner 
whorls have been drawn from the opposite side of the specimen. So 
far, then, as the outer whorl is concerned, the photograph reproduced 
in the Palontologia universalis represents the opposite side of the 
specimen to that figured in the Mineral Conchology, and, in a great 
measure, accounts for the striking differences between the figure in 
the Palgontologia universalis and Sowerby’s figure. Even if the 
specimen had not been labelled in Sowerby’s handwriting, there could 
be no doubt whatever about its identity, since the details of the septal 
surface at its anterior end have been carefully copied in Sowerby’s 
figure. 
2. Ammonites excavatus.—-Miss Healey gives the date of publication 
of this species as 1818. It is true that this is the date on the title- 
page of the volume (vol. ii) in which that species was described and 
figured (p. 5, pl. cv), but, as has been mentioned above, the Jhneral 
Conchology was published in numbers or parts; and vol. ii included 
Nos. xix—xxxv, which were issued between October 1, 1815, and 
June 1, 1818, both dates inclusive. The figure and description of 
Ammonites excavatus appeared in No. xix, which is dated October 1, 
1815. The date of publication of the species should therefore be 1815, 
and not 1818. 
1 The dedication of the work, and each plate in No. i, which included pls. i-iii 
with explanatory text, is dated May 25, 1812. 
| 
| 
