10 AUBICtJLID^:. 



and Auricula australis was made the type of a new genus, Ophi- 

 cardelus, adopted more recently by Gray, Morch, and H. and 

 A. Adams, but forming in L. Pfeiffer's Monograph only a sec- 

 tion of Melampus. The genus Tralia, founded by Gray (1840) 

 for a species " having a simple internal lip, with a subposterior 

 internal groove, where the notch occurs in Sidula," adopted by 

 Morch, and in wider limits by H. and A. Adams, may also form 

 a part of Melampus, although the foot of Melampus is said to be 

 bifid posteriorly, and that of Tralia entire and acute. But even 

 the typical species of Melampus, Auricula coniformis, Lam., the 

 animal of which has been observed by Pfeiffer and others, has 

 the foot entire, and the animals of the greater number of spe- 

 cies are unknown. The subgenera Pira, Persa, &c. of H. and 

 A. Adams seem to be founded on characters which are only 

 fit for distinguishing species, but not subgenera. 



The species of Melampus may be divided into the following 

 sections : — 



A. Labrum with parallel internal plaits. 



a. Body of the penidt whorl not plicate 



(Detracia, Gray) § 1 No. 1- 5 



b. Body of the penult whorl with 1 plait . . § 2 - 6-17 



c. „ „ „ with 2 plaits . § 3 - 18-32 



d. „ „ „ with 3 plaits . § 4 - 33-^1 



e. „ „ „ with more than 



3 plaits . § 5 - 42-43 



B. Labrum strongly plaited §6 - 44-46 



C. Labrum with a single internal transverse rib § 7 - 47-53 



D. Labrum not plaited : — 



a. Body of the penult whorl smooth .... § 8 - 54-55 



b. „ „ „ with 1 single 



plait (Ophicardelus) § 9 - 56-61 



c. „ „ „ with 2 plaits § 10 - 62-65 



E. Doubtfid species § 11 - 66-68 



§ 1. Labrum furnished tcith more or less distant parallel trans- 

 verse ribs ; body of the penidtimate whorl destitute of plaits. 



Detracia, Gray. 

 1. Melampus commodus. 



Shell rimate, oblong-ovate, rather solid, slightly shining, 

 chestnut-coloured; spire conic, with the apex pointed ; suture 

 bordered; whorls nine, flat, the upper ribbed radiatingly, the 

 last forming nearly two-thirds of the total length, rather smooth, 

 somewhat turgid above, attenuated at its base ; slightly gibbous 

 and striated ; aperture nearly perpendicular, acuminately semi- 

 ovate ; no parietal plait ; columella!' plait short, oblique, some- 



