The nuclei of Recent beach specimens are nearly always damaged, but very fine specimens—mostly of the closely related A. swainsoni Marwick (= elongata Swainson)—can be obtained from the Upper Pliocene sands of Castlecliff, Wanganui.

As can be seen, these exhibit considerable variation in shape, especially in the height of the blunt point. There can be no doubt that this shelly apex represents the stage which follows a horny protoconch, and which was named by Dall “scaphelloid.”

The specimen illustrated in text-fig. 1d shows an abnormal condition. The walls of the bulbous top are 0.5 mm. thick, and the chamber is continuous with that of the shell. Apart from this, there are no signs of irregularity in the growth of the specimen.

The nucleus of A. gracilis resembles that of A. arabica except that it is somewhat flatter.

Harris (1897, p. 113), dealing with fossil material, recognized these features and classed both species under Scaphella, doubtfully including in the same genus V. ancilloides Tate from South Australia. He stated that his single specimen of the latter shell was without its protoconch, which according to Tate appeared to be bulbous, and therefore the generic position might be nearer Fulgoraria.

Fig. 1.—Alcithoe swainsoni n. sp. Apices of specimens from the Pliocene of Castlecliff. × 6.

Hedley (1906, p. 49), in pointing out the priority of V. arabica over V. pacifica, also placed the species under Scaphella. Later (1914, p. 725) he granted Alcithoe generic rank, noted its close relationship to Adelomelon, and stated that records of Australian occurrences were incorrect.

When Cossmann revised the family he apparently did not have access to specimens of the genotype of Alcithoe, for he compiled his diagnosis (1899, p. 132) from two South Australian species, V. fulgetrum Sowerby (Recent) and V. ancilloides Tate (Janjukian), neither of which is closely related to V. arabica. As a result he described the protoconch as bulbous, larger than the first whorls of the spire, and sometimes ornamented with ribs. He also gave a figure of the laterally rolled protoconch of V. ancilloides, and placed Alcithoe as a subgenus of Fulgoraria. This example was followed by Suter, who dealt mostly with Recent shells and did not notice the true nature of the apex of V. arabica as shown by the well-preserved fossil specimens.

The genus Fulgoraria Schumacher is founded on a rare shell, V. rupestris Gmelin, which, in addition to the lateral bulbous protoconch, has a rather attenuated anterior canal which is not notched. Other distinctive features