Thanks SPW for his history of Aptychus, which makes A. D. d'Orbigny's view [that it is a cirripede] improbable. [See Fossil Cirripedia 1: 3.]
Specimens SPW sent are very useful and interesting.
Down Farnborough | Kent
My dear Sir
I am extremely much obliged to you for taking the trouble to give me so clear & succint a resumè of the history of Aptychus with your capital little sketches. I will come sometime to the Museum, & beg you to show me some specimens.— The facts you state (& a few specimens seen by me) appear to me to render d'Orbigny's view, a priori, so improbable, that I hope a very short inspection will suffice for me.— I am far from anxious to drag anything into Cirripedia; with my small powers of work the order is now enough & too much for me.—
The (3) specimens which you gave me from Norwich were very useful to me, & well
exemplify Pollicipes maximus & sulcatus of Sowerby, which I consider varieties
of one species of Scalpellum.— The two specimens
from the Grey Chalk have turned out very interesting: one I have described as a new
species, & the other is a very rare one, seen by me
only in M
I have not heard from the Dover man, & I fear you have not heard from the
Norwich collector.— I am very sure dozens more species of Cirripedia will turn
up— I wrote from your suggestion to M
Your's very sincerely | With thanks | C. Darwin
Kind remembrances to Waterhouse
- f1 1314.f1In CD's time, Aptychus was considered a genus of some fossil organism and constituted a biological puzzle. It is now known to be a horny plate or lid found in fossil ammonites.
- f2 1314.f2Alcide d'Orbigny maintained that Aptychus was a pedunculate cirripede (Orbigny 1849–52, 1: 254–7). CD argued against this view in Fossil Cirripedia (1851): 3–5. He believed there were good morphological reasons why Orbigny was wrong. But in addition to this he suggested a reason which, he said, ‘will have weight, perhaps, with only a few persons’ (p. 4). The fossil, which has upward-directed ‘valves’, occurs in the Carboniferous formations, much earlier than the earliest known cirripede, Pollicipes. In the latter the direction of the valves is downward. Upward direction in valves occurs only in late Tertiary cirripedes. Thus if Aptychus were a cirripede it would occupy an anomalous place in what CD called the ‘order of creation’, and would violate what he elsewhere referred to as ‘the law of relation between serial affinities of animals and their first appearance on this earth’ (‘British fossil Lepadidae’, Collected papers 1: 252; see also Fossil Cirripedia (1851): 5). CD saw a close relation between the age of fossil Lepadidae and the upward or downward direction of the lines of growth in their valves.
- f3 1314.f3See Fossil Cirripedia (1851): 26–35.
- f4 1314.f4Probably Scalpellum hastatum (Fossil Cirripedia (1851): 37).
- f5 1314.f5No Grey Chalk specimen from Bowerbank's collection is listed in Fossil Cirripedia (1851). It is possible that CD refers to specimens of a variety of Scalpellum arcuatum, although he stated that the two specimens came from the British Museum and John Wickham Flower respectively (Fossil Cirripedia (1851): 41–2).
- f6 1314.f6James Tennant, professor of mineralogy, King's College, London. In the preface to Fossil Cirripedia (1851), CD mentioned Tennant among those who supplied him with specimens of species that were new to him. The valves were identified as coming from Pollicipes bronnii (ibid., pp. 77–8).