IKKDALE : OX KEEIIADEC MOLLUSCA. 221 



and the higher two major tlireads are further apart, and between 

 thera are five to eight minor tlireads. 



Measurements of type: Length 12, breadth 5mm. 



Jlab.Sumlnj Island, Kermadec Glroup. 



The animal examined alive was of a white colour; eyes sessile as 

 black specks ; propodium square, whilst the radular characters are 

 such that it might be referable to Caiit/uirus or Pisania. 



QuoTULA, n.gen. 



This is introduced for the shell described by Quoy & Gaimard as 

 Purpura monodonta ( Voy. de I'Astrol. Zool., vol. ii, p. 561, pi. xxxvii, 

 figs. 9, 10, 1833) from Tongatabu. 1 have given the history of its 

 Avanderings from Coralliophila through Rhizochilus and Galeropsis 

 back to Curalliophila (these Proceedings, vol. ix, p. 76, 1910). I was 

 inclined to let it stay in Coralliopliila through the prejudice of the 

 Sinusigera apex, but study of this shell with tlie other forms assigned 

 to that genus has convinced me of the impropriety of so doing, and 

 the only course open is to separate it. 



Coralliophila was introduced by H. & A. Adams in the Genera 

 Recent Mollusca, vol. i, p. 135, 1853, as a sub-genus of Rhizochilus, 

 and, though sixteen species were named as members of the genus, no 

 type was selected. l)all (Bull. Mus. Comp. Zool. Harv., vol. xviii, 

 p. 217, 1889) noted this, and remarked that C. maclreporarum could 

 not be accepted as type, as it was not one of the original members of 

 the sub-genus, but made no designation of type, adding " the true 

 Coralliophila has been renamed Fseudomurex^'. Cossmann (Essais 

 Paleoconch. comp., Livr. v, p. 83, 1903) has named as type '^Purpura 

 neritoidea, Lamk." In Adams' List is a "■ neritoideus, Chem.", so 

 I would fix this as type. With this species I do not consider Quoy & 

 Gaimard's P. monodonta congeneric, neither do I now accept 

 P. madreporarum, iSowerby {Gen. Rec. Fossil Shells, vol. ii, pi. 237, 

 tig. 12, 1834) as conspecific with the latter. "When looking up this 

 I noticed a footnote reading, " Since the above was written Mr. Gray 

 has separated the last-mentioned shells from Purpura, under the 

 generic appellation of Pallia." This refers to the sentence " Triton 

 undosiis of Lara. : we suggest the probability of its forming a well 

 distinguished genus in union with several other cognate species". 

 In the British Museum copy of Sowerby's work Mr. Edgar A. Smith 

 has noted that Pollia was not published by Gray until 1839 in 

 the Zoology of Beechey's Voyage ; this latter has generally been 

 quoted as the first entrance of Pollia, whereas Sowerby's note has 

 five years priority. Moreover, the type (by monotypy) of Pollia, 

 Soweiby, 1834, is T. undosus, Lam., so that Tritonidea, Swainson, 

 1840, would become an exact synonym, though probably both fall as 

 equivalent to Canthartis, Bolten, 1798. 



Heterorissoa, n.gen. 



Shell minute, rissoid, smooth and shining, thin, glassy, transparent. 

 Aperture broadly oval, peritieme thin, not continuous. Operculum 



