ARCA.
Testa crassa, umbonibus distantibus intus fornicatis. Cardo planus, masticatus dentibus numerosis minimis æqualibus transversis.
A. tortuosa. A. oblonga obliqua, valvula altera oblique carinata.
"Nates, &c." and "Cardo, &c." were the printed additions to the earlier description. The 'Systema' synonyms of Klein (t. 8. f. 16) and Bonanni (2. f. 128) were present in the manuscript.
A. Noæ. A. oblonga angulata hians.
This manuscript furnishes us with the additional synonyms of
"Aldrov. 3. p. 513." and "Sloan. Hist. 2. p. 257. Musculus Matthioli," besides the previously published references to Lister (368. n. 208) and Bonanni (2. t. 32). The formation of the hinge was not, however, indicated, and the passage commencing with "Nates" has been enlarged from "Umbones remotissimæ, area interjecta concava, ad angulum rectum striata. Margo exterior in medio hians, apertura barbata."
The intended specific epithet was A. Noemi.
A. antiquata. A. testa oblique cordata, transversim sulcata, antice angulo compresso, rima intra rhombum transversim striata.
The admixture of two species (at the least) in the published edition resulted from the amalgamation of two earlier descriptions. To the above diagnosis belonged the printed details with the following important changes. In place of "extus striata longitudinaliter sulcis crenatis," the reading was simply "intus striata longitudinaliter," and in lieu of "interjecto spatio rhombeo plano," merely "rima patens."
The proposed name for this shell, from a supposition of its identity with the Pecten virgineus of Rumphius, was A. virginea. The other species which Linnæus referred to the same numerals of the 'Systema' was not named, but was thus characterized:—
A. (Sys. n. 144). A. cordata, sulcis nodosis, rima decussatim striata.
List. Hist. ... Pecten polyleptoginglymus, &c.
Gualt. t. 87. f. C.
Testa reliquis magis gibba, albido-flavescens, sulcis xxx obtusis, transversim nodosis: nodis transversis, obtusissimis, imbricatis. Intus albida. Margo dentibus xxx argutiusculis. Rima sulco rhombeo circumscripta, disco decussatim vix manifeste striato. Umbones distantes ad neutrum latus flexi.
A. senilis. A. oblique cordata, octosulcata, lævis, antice hians, rima obtusangule striata.
Lister (without numerals!) was referred to in illustration; the early unimproved account of the beaks and ligamental area ran as follows: "Umbones distantes, oblique incurvati. Rima hians striata transversim ad angulos acutos": "et profunde immersis" was an addition.
A. granosa. A. subcordata, sulcis muricatis, rima obtusangule striata, utrinque angulum formante.
The name was evidently borrowed from Rumphius, whose Pecten granosus ("143. t. 44. f. K.") was referred to in the manuscript, though neither quoted in the printed copy nor in the 'Systema' (ed. x.). "Bonan. 2. n. 73," and Lister (without numerals) were also cited.
A. decussata. A. lenticularis, decussatim substriata, apicibus reflexis.
For a detailed account of this shell, to which no specific name was attached in the MS., the 'Museum Ulricæ' was referred to, previous to its publication.
A. pallens. A. lenticulari-subobliqua, decussatim striata, rima brevi.
This was the type referred to in the 'Systema.'
A. pectunculus. A. lenticularis sulcata, decussatim rugosa.
"Arg. t. 27. f. B," and Lister without numerals appended, were the unpublished synonyms. The expressions "leviter," "exteriore tenui; sulcata," "in arcum," were not parts of the original copy, which contained, however, the unprinted paragraph "latere interiore margine prominente notato." There was no specific name attached to either this or the next species.
A. glycimeris. A. lentiformis, transversim substriata, rima lævi.
The 'Chama glycimeris Bellonii' of Lister (t. 247) was an unprinted synonym.
The following suppressed description of an unnamed Ark that was allied to, if it were not, fusca or barbata, was found in the manuscript. The 'Museum' had been referred to in the synonymy of the latter in the 'Systema,' but the species was not mentioned in the published version.
Arca ovalis, compressiuscula, apicibus subcontiguis.
Testa rudis, ferrugineo-fusca, longitudinaliter striata, striis quasi ex punctis callosis concatenatis, alternis striis majoribus ovatis, parum obliqua, minus lateribus gibba, rotunda absque angulis. Margo æqualis, edentulus. Apices recurvi fere tangunt se invicem. Rima dentibus minutissimis, antice longius extensa, nec recta.