MAZATLAN UNIVALVES 351 



SECTION 33. 



Shell large, Pliasianelloid, rather thin, coloured ; columella 

 excavated. Animal amphibious ; oftea found crawling up trees 

 at a considerable distance from the sea (Dyson J = Melaraphe, 

 pars, H. fy A. Ad. Gen. vol. i. .p. 414: ?non Melaraphe. 

 MiiJilfeldt. When convenience requires the subdivision of 

 Litorina, this group, included ; foy Lam. in Phasianella, will 

 probably be found natural. 



/ 



4/30. LITORINA FASciATA/-'GWy. 



Zool. Seech. Voy. p. 139. &ieb. in Wiegm. Arch. p. 209. Phil. 



AbUld, pt. ii. p. 37, pi. 5, f. 1, 2.Mke. in Zeit.f. Mai. 1850. 



p. 163, no. 7. C. IB. Ad. Pan. Shells, p. 173, no, 236. 



H. $ A. Ad. Gen. i. 313. 

 + Melaraphe fasciata, H. fy A. Ad. Gen. i. 314. 



This very beautiful species, of which but few specimens 

 were found, is (as Menke remarks) intermediate between 

 L. pulchra and L. scabra. The spire is pointed, never eroded. 

 When young it has fine spiral stria?, and is somewhat highly 

 coloured with orange and purplish brown in irregular bands 

 or dashes. When adult, it is often nearly smooth, with the 

 colour evanescent near the labrum. The operculum is very 

 thin, with but few turns, and the nucleus not far from the 

 middle. Surface not granulose, with rather coarse stria? of 

 growth. The largest sp. measures long. 1'16, long. spir. '64, 

 lat. '95, div. 60. 

 Hob. Tumbez, Peru, Ouming. Panama ; not uncommon, 



with L. varia, on trunks and branches of small trees growing 



between half tide and high water levels ; C. B. Adams. 



Mazatlan ; very rare ; Upool Col. 



Tablet 1687 contains the most characteristic specimen, with 

 its operculum ; also a very young shell ; and a loose operculum. 



GENUS MODULUS, Gray. 



Phil Handh. Conch, p. 176. .H". Sf A. Ad. Gen. vol. i. p. 316. 

 A. Ad. Hon. in Proc. Zool. Soc. 1850, p. 203. . 



= Monodonta, Swains. = Monodonta, pars, Lam. Shell not 

 pearly, generally Trochiform, with a deeply grooved colu* 

 mellar tooth. Operculum multispiral. 



