Iredale. — Sitter's " Manual of the New Zealand Mollusca." 491 



The nomination of the species and groups would read, — 

 Genus Amphidesma Lamarck. 1818. Am/phidesma Lamarck, Hist. Nat. 

 Anim. s. Vert., vol. v, p. 489, 1818. Type (by tautonymy) : A. dmta- 

 cilla Lamarck-. 

 Subgenus Taria Gray, 1853. 



Amphidesma gaymardi (Deshayes, 1832). Synonyms: Mesodesma 

 subtriangulata Griffiths and Pidgeon, 1834 ; M. spissa Reeve, 

 1854. 



- quoyi (Deshayes, 1832). Synonym : Mesodesma lata Deshayes, 

 1843. 

 — ventricosum Gray, 1843. Synonym : Taria stokesii Gray, 

 1853, n.n. 

 Subgenus Paphies Lesson, 1831. Synonym: Mesodesma Deshayes, 1832. 

 Amphidesma australe Gmelin, 1791. 

 — — — ■ — var. aucldandicum Martens. 1879. 



Amphidesma gaymardi (Deshayes, 1832). [P. 957.] 



This is the name to be used for the species included by Suter as Meso- 

 desma subtriangulatum Gray, 1825. 



First, " Erycina subtriangulata Gray, Thomson's Ann. Philos., xxv, 

 1825," does not occur. Observe that no page is given. In the Ann. Philos. 

 (Thomson), vol. xxv, also quoted in n.s., vol. ix. 1825, Gray gave a list of 

 species not noticed by Lamarck, and on p. 135 is " Ery(cina) subangulata. 

 < Wassatella cuneata Lam., 483 ? ' Note the spelling of the specific name, 

 and, as the above is the complete entry, it is quite obvious that it is a 

 nomen nudum. The first synonym, *' Mesodesma latum Deshayes, 1843," 

 does not belong here : the figure negatives the association instantly. Des- 

 hayes wrote " lata." Meanwhile, in Griffith and Pidgeon's " C'uvier's Animal 

 Kingdom," on pi. 22, fig. 4. a shell was figured under the name Mesodesma 

 subtriangulata. Suter has placed this entry in the synonymy of Mesodesma 

 australe Gmelin. 1790. writing. " not of Gray, 1825." I know Suter has 

 never seen this plate, as the figure in no way resembles Mesodesma australe. 

 The figure shows a shell quite like the present species, and, allowing for 

 faulty draughtsmanship, is a fairly good illustration. The shell from which 

 the drawing is supposed to have been made, the name being written on 

 the back of the tablet, is still preserved in the British Museum, and is un- 

 doubtedly this species. However, in the Ency. Meth. Vers., vol. ii, p. 444, 

 1832, Deshayes named and fully described Mesodesma gaymardi from a 

 specimen brought back from New Zealand by Quoy and Gaimard. In my 

 opinion, no name could be more suitable. I have associated this species 

 with ventricosum Deshayes in the subgenus Taria, as superficially there does 

 not seem much distinction. Comparing A. quoyi (Deshayes) with the pre- 

 sent species, I note that both have the siphonal inflection small, whereas 

 A. ventricosum has the siphonal inflection deep. Suter, in his definition of 

 Taria, copied from Dall, writes, " pallial sinus well marked, sometimes 

 deep.*' The type of Amphidesma, though approaching this species A. gay- 

 mardi, has a long siphonal inflection, so that it seems a variable character.* 



*I find Lamy (Bull. Mus. Hist. Nat. (Paris), vol. xviii, 1912, has investigated the 

 nomenclature of the Neozelanic forms, and has shown that Mesodesma lata Deshayes, 

 1843 = M. quoyi Deshayes, 1830, and that this is quite distinct fr< m M. ventricosa Gray. 

 My own results were achieved in ignorance of Lamy's prior work, so that my con- 

 firmation is pleasing. Lamy has also gone further than myself with regard to the 

 present species, as he has sh r wn that subtriangulata can be retained as of Wood : Index 

 Test. Suppl., pi. i, fig. 10, 1828 [Mactro). 



