from New Zealand. 301 



as being the most likely genus. It also resembles Vanikoro, but the 

 shell seems too thick and the inner lip too strongly developed. 

 The partial detachment of the inner lip from the body-whorl and the 

 complete peristome suggests the genus Fossarus, which together with 

 Vanikoro has a horny operculum, whereas that of Neritopsis is thick 

 and stony. There is no trace of columellar folds nor of a reflected lip 

 which might connect it with Cinulia or Eriptyclia. 

 . The erosion or battering which the spire has suffered in the adult 

 specimen points to its being some shore-loving form, but whether of 

 the Littorinidse or INeritopsidse is uncertain, but I think the genus 

 Neritopsis is the more likely one. 



Locality. — Selwyn Rapids. 



The only species I can trace which at all resembles the present 

 form is Vanikoro Kiliani, Wilckens, 1 which occurs at Snow Hill and 

 Seymour Island in Antarctica. But this is a very small shell and 

 consists only of three to four whorls and has fourteen spiral ribs, the 

 spaces between which are not always equal and the ribs are preserved 

 only on the last whorl. I take the opportunity of naming this shell 

 after my friend Dr. B. Speight, director of the Christchurch Museum, 

 who has published many papers on New Zealand Geology, and who 

 assisted me to collect several of the Cretaceous fossils. 



CONCHOTHYEA PARASITICA, JVlcCoy. (PI. XX, FigS. 4, 5.) 



Hector, Cat. Ind. and Col. Exkib., 1886, p. 58, fig. 4. 

 Park, Geol. New Zealand, 1910, p. 90, pi. v (after Hutton). 



This extraordinary Gasteropod is the most abnormal of the curious 

 group of the Pugnellids. The smooth callosity of the inner lip 

 is more exaggerated than in any other species of the group, and 

 in some specimens it extends beyond the apex and sometimes almost 

 buries the spire. The thickened claw-like outer lip is very large and 

 heavy, and the growth-lines and ridges on the body-whorl are very 

 exaggerated. 



If the genus Conchothyra is to be retained — and in view of its 

 frequent mention in New Zealand geological literature and the great 

 specialization of the shell in question I think it should be — it may be 

 re-defined as follows: — 



Shell as in Pagnellus, but the early whorls are smooth and devoid 

 of nodes or ribs. Spire short and in fully grown specimens almost 

 buried by the labial callosity, and often scarcely visible owing to 

 erosion. The lines and ridges of growth are coarse and prominent 

 on the last whorl. The anterior channel of the mouth is deep and 

 narrow, the posterior channel is shallower and more or less semi- 

 circular in shape. The outer lip is much thickened and often greatly 

 prolonged. 



I think this curious mollusc may have been of a sluggish character 

 and have lain partly buried in sand. Both the great weight of the 

 shell and its frequent erosion suggest this mode of life. That part of 

 the body-whorl on the back below the spire is generally very thin, 



1 "Die Anneliden, Bivalven, u. Gasteropoden der antarktischen Kreicle, 

 1910" : Wissensch. Ergebnisse der Schwed. Sudpolar Exped., p. 77, pi. iii, 

 tigs. 28a, b. 



