Achatina balteata variety infrafusca E. von Martens

Figure 6
Achatina dimidiata E. VON MARTENS, 1889, 'Conch. Mitth.,' III, parts 1-2, p. 17, P1. XLII, figs. 1-la (type; "ad oram Fl. Gabun," French Congo). Not of E. A.
Smith, 1878.
Achatina infrafusca E. VON MARTENS, 1897, 'Deutsch Ost-Afr., IV, Besch.
Weichth.,' p. 89 (new name for A. dimidiata E. von Martens, 1889). Achatina balteata var. infrafusca PILSBRY, 1904, 'Man. of Conch.,' (2) XVII, p.
32, P1. iv, figs. 22-23. SPECIMENS EXAMINED.-One specimen from Lukolela, Belgian
Congo (J. P. Chapin.-A. M. N. H.). Four specimens from the Gaboon
(M. C. Z. and A. N. S. P.). Two specimens from Lambarene on the Ogowe River, Gaboon (Mrs. L. Russell.-A. N. S. P.). This variety is characterized by the pronounced, more or less wavy, chestnut stripes which extend over all the whorls, but are lacking on the lower half of the last whorl. In the typical form-, only the early whorls have a few vertical chestnut blotches. Moreover, as Pilsbry has pointed out, there are transitional specimens. It has been claimed that infrafusca has also a proportionately shorter and broader shell than typical balteata; but this is not borne out by E. von Martens' measurements of
the type of infrafusca (length, 120; width, 60; aperture, 59 X 32 mm.), nor by specimens we have seen. According to Dr. J. P. Chapin's notes, the living specimen which he photographed at Lukolela (Fig. 6) had the dorsal surface of the extended animal behind the shell light yellowish-gray, shading to blackish on head and tentacles. The variety infrafusca does not seem to be geographically segregated and is hardly worth retaining. Among the specimens listed above from Bathurst, Gambia, one is intermediate between the typical coloration and the variety infrafusca, having on the body whorl a series of chestnut streaks faintly confluent at the periphery into a spiral band
which becomes more pronounced behind the outer lip.

 

 

Achatina iostoma Pfeiffer

Figure 7
Achatina iostoma PFEIFFER, 1854, Proc. Zool. Soc. London, (1852), p. 86 (Fernando Po); 1867, 'Conch.-Cal.,' I, Abt. 13, part 1, p. 360, P1. XLIII, fig. 7 (type from
the Cuming Collection). PILSBRY, 1904, 'Man. of Conch.,' (2) XVII, p. 32, P1. xviI,
fig. 18, and P1. XLII, fig. 10.
Callistoplepa tiara PRESTON, 1900, Ann. Mag. Nat. Hist., (5) VI, p. 183, P1. vi,
fig. 9 (type; Bitye [misspelled Bitzel, near the River Ja, Cameroon).
Achatina gruveli DAUTZENBERG, 1921, Rev. Zool. Afric., IX, p. 91, P1. vi, figs.
1-2 (type; Yaunde, Cameroon, at 780 m. altitude).
SPECIMENS EXAMINED.-Two adult shells from Elalawa (Elat), Cameroon (A. N. S. P.). One adult and six young shells from Yaunde,
Cameroon (A. N. S. P.; M. C. Z.). Two adult shells from Metet, Cameroon (A. J. Good.-M. C. Z.). One adult shell from Bipindi, Cameroon (A. J. Good.-Carn. Mus.). One adult shell from Efulen, Cameroon (A. N. S. P.).
Although originally described from the Cuming Collection as coming from Fernando Po, A. iostoma has never again been taken on that island and the type locality is extremely doubtful. The species is known with certainty from western Cameroon only, where it is common in many localities. A. iostoma is readily distinguished from A. balteata by the much coarser, very tangible, beaded sculpture, which covers more uniformly
the entire surface of the shell. The beads are placed in regular spiral
and slightly confluent, vertical rows over the entire width of the body
whorl. Some eighteen to twenty beads may be counted on the upper half of the body whorl, right behind the aperture, in a vertical stretch of one centimeter.

As pointed out by Dupuis [1923, Ann. Soc. Zool. Belgique, LIII
(1922), p. 81], Callistoplepa tiara Preston was based upon a young Achatina. We do not hesitate in referring it to A. iostoma. We have before us a young shell of that species (55 mm. long, of 6 whorls), from Yaunde, which agrees in every detail with Preston's description and figure. Bitye is on the Ja River, about seventy miles to the southeast of Yaunde.
Some of our specimens of A. iostoma agree in every respect with Dautzenberg's figures and description of his A. gruveli, which, in our opinion, was based upon young specimens of iostoma (95 mm. long, of 7 whorls). As yet we have seen no true cotypes of gruveli; but specimens referred to that species at the A. N. S. P. (some of them apparently named by Dautzenberg) are certainly young iostoma. They have the "hydrophanous" streaks mentioned by Dautzenberg for gruveli; but
such streaks are often present in true iostoma, as well as in related species (for instance, in A. bandeirana).