becoming faintly yellow in large specimens; spire low, rounded; keel of moderate height, with a slightly truncated leading edge and a base that changes from clear to dark yellow-brown with age||10||3-1/2 to 3-3/4 ||b||b ||II ||+||+||+|
|A. fragilis||Shell fragile (very thin-walled), transparent and completely colorless; keel tall with a truncate leading edge and a clear base||9||3-1/2||b||b||II ||+||-||-|
|A. rosea||Spire rounded and nearly globular, due to the shallow sutures of first two and one-half whorls; color faintly yellow; species name based on bright pink color of larvae ||5||3-1/2||b||b ||II ||+||+||+|
|A. frontieri||Spire low, with first and second whorls elevated, forming a low cone; distinctive thin, elevated spiral ridge along outer margin of spire whorls; keel tall and rounded; shell clear ||5.5 ||4-1/2||b||b ||II ||-||+||+|
|A. gaudichaudi- group||Shell flat, with a moderately small maximal size; spire shape low conical; radula type I, with monocuspid lateral teeth ||A. gaudichaudi||Spire low conical and surface lacks sculpture; keel of tall, with a truncate leading edge; keel base yellow- or red-brown ||3||3-1/4 to 3-1/2 ||b||b ||I ||+||+||+|
|A. plana||Spire low conical with two low spiral ridges on second and third whorls; spire sutures violet; keel moderately low and rounded, with a yellow- or red-brown base; opercular gyre with spiral row of spines ||4||3-1/2||a||b ||I ||-||+||+|
|A. echinogyra||Spire moderately low conical, slightly tilted relative to the shell plane; spire with prominent spiral ridges and red-violet to red-brown color ||2.5||3-3/4||a||c ||I ||-||+||+|
|A.inclinata- group||Shell spire large, with globose shape, and tilted (inclined) relative to shell plane; spire whorls with shallow sutures and numerous small tubercula; internal spire walls decalcified; inner surfaces of spire whorls with radial lines; keel tall and rounded||A. inclinata||Shell clear to light yellow; tubercula scattered on surface of spire ||6-7||5||b||c ||II ||+||+||+|
|A. tokiokai||Shell light yellow-brown and inside of outer lip of brown; spiral rows of tubercula on spire ||3||5-1/2||b||c ||II ||+||+||+|
|A. gibbosa- group||Shell spire large and tall; shell transparent and colorless, with thin walls; inner surfaces of spire whorls without radial lines; keel tall with truncate leading edge ||A. gibbosa||Spire moderately tilted relative to shell plane, with a broad conical shape; umbilicus large and very wide ||4||6||b||b ||II ||-?||+||+|
|A. meteori||Spire strongly tilted relative to shell plane, with a narrow conical shape; umbilicus small and narrow ||4||5-1/2 to 5-3/4||b||b ||II ||+||+||+|
*One species, Atlanta peresi, is not included in the table above because it is most probably not valid. It was described by Frontier (1966) from the western Indian Ocean off Madagascar. Although its adult shell morphology and opercular type were characterized by Frontier, its eye and radular morphologies are unknown. Unfortunately, no specimens from Frontier's collections have been found for further examination. Catherine Thiriot (pers. comm. to R. Seapy) had thought that Frontier's collections might have been deposited at the Observatoire Océanologique, Villefranche-sur-Mer, France; but her search for these collections proved futile. Richter (1974) concluded that there was substantial doubt that A. peresi was a valid species after his examination of the heteropods from the extensive collections of the Meteor Expedition in 1964-1965 to the northwestern Indian Ocean, including the Arabian Sea. In addition, examination of planktonic and benthic samples collected off western Australia (Seapy et al., 2003) did not record any specimens that could be identified as A. peresi. There have been no records of the species from the Pacific Ocean (Seapy, 1990a,b and 2008; Newman, 1990), although it was identified from the North Atlantic by Thiriot-Quiévreux (1968, 1970 and 1973). However, she subsequently concluded that the identifications were erroneous (R. Seapy, pers. comm.). The interested reader is referred to Richter and Seapy (1999