476 mr. g. f. angas on the [June 3, 



the apex, which is somewhat obtuse ; base very slightly convex ; 

 aperture very oblique, subquadrate ; outer lip expanded and sinuous 

 above, with a produced horizontal beak at the periphery, arcuate and 

 somewhat reflexed below. 



Diam. maj. 13|, min. 10, alt. 10 lin. 



Hab. Along the Zhorquin river, Costa Rica. 



" Animal very slender, nearly white, pale brownish on head and 

 top of body" (Gabb). 



Five adult and three young specimens found, all of the same 

 coloration. 



This very remarkable and elegant shell is the gem of the col- 

 lection. It belongs apparently to the same section as H. bifasciata 

 from Brazil. 



2. Helix ^esopus, Angas, P. Z. S. 1878, p. 72, pi. 5. figs. 

 11, 12. 



Some of the specimens show a dark band round the umbilical 

 region, and are larger than the type specimen figured in the Zoological 

 Society's ' Proceedings,' whilst one of them shows traces of con- 

 centric lines, especially towards the front of the last whorl. 



The nearest ally to this species is H. triplicata, Martens, which, 

 however, is smaller, and differs in the shape of the peritreme. 



" The animal is grey above, with the foot nearly white " (Gabb). 



Found in the coast region and to the hills of Uren, at an altitude 

 of 3000 feet. The type specimen was found at Buena Vista at a 

 similar altitude. 



Seventeen specimens found, five only unbleached. 



3. Helix mac-neili, Crosse, Journal de Conch, vol. xxi. p. 67. 



Of this small species only three fresh specimens and a few dead 

 ones were found. 



" Animal dark brown ; tail and foot slightly lighter ; upper ten- 

 tacles long" (Gabb). 



Coast region and lower hills, from Parismina to the hills of 

 Zhorquin. 



4. Helix costaricensis, Roth ; Pfr. Mon. Hel. iv. p. 302; Pfr. 

 Novitat. i. 21. 15-17. 



This is an extremely variable species, both in colour and form as 

 well as in size ; still I cannot detect in the series before me any dif- 

 ferences that would amount to specific characters. The base is 

 invariably white, with a dark-brown umbilicus, and the umbilical 

 region tinged with bright yellow. The three principal varieties 

 appear to be : — 1st, large, depressed, white, with two or three narrow 

 dark-brown bands ; 2nd, small, depressed, with the upper surface 

 light or dark brown throughout, or zoned with both colours ; 3rd, 

 medium in size, much more conical, with two broad bands of light 

 brown, or all light brown above. This last variety was described by me 

 in this Society's 'Proceedings' for 1878, under the name of Helix bou- 

 cardi, from specimens brought home by Mons. Boucard from the region 



