476 NOTES ON PROSOBRANCHIATA, 



** convergence of development " rather than a real affinity; for if 

 the species of this group have been evolved from ancestors orna- 

 mented with a complex sculpture, it was at an earlier period than 

 that at which L. parkinsonianum was evolved, since none of them 

 show any sign thereof on their early whorls. Further, two species 

 belonging typically to the tritonis-grow^ occur in Tertiary strata 

 — L. ovoideum, Tate, from Australian beds, and L. nodi/erum, 

 Lamk., which has been recorded from Mediterranean beds by 

 Hoernes and Auinger (is). 



LoTORiUM PiLEARE, Linn. 



For this species Linnaeus quoted figures of two species, and 

 described a third. Hanley (14) says his type, on which his 

 description was founded, was the Triton corrugatus of Lamarck, 

 and refers to Reeve's figure in the ' Conchologica Iconica' (pi. v., 

 f. 15). The first of these three species to be recognised as distinct 

 was Lotorium costatum by Born in 1780. Lamarck, in dealing 

 with the species, unfortunately bestowed a new name on Linnaeus' 

 type, and retained the name pilearis for the species, which has 

 since been known under that name. 



The principles of nomenclature, however, require that in 

 eliminating from an heterogeneous group, the name originally 

 bestowed thereon shall be retained for the type when that t3'pe 

 is available. 



The synonymy of these two species will, therefore, stand thus : — 



Lotorium pileare, Linn. H 



'i 



Mur ex pilearis, Linn., Syst. Nat. 1767, p. 1217, sp. 534. 

 Triton corrugatus, Lamarck, An. s. Vert, vii., 1822, p. 181; Reeve, 

 Conch. Icon. ii. ''Triton,'' pi. v., f. 15, 1844. 



Lotorium aquatile, Reeve. 



Triton pilearis, Lamarck, An. s. Vert. vii. 1822, p. 182 (non Linn.). 

 Triton aquatilis, Reeve, Conch. Icon. ii. " Triton,'' pi. vii., f. 24, 



April 1844; P.Z.S. 1844 (December), p. 114. 

 Triton vestitus,^A\x\^^, Zool. Voy. Sulphur, "Mollusca," Oct. 1844; 



P.Z.S. 1844 (July), p. 21. 



