PARTULA. 157 



The coloration in all the species varies from pale cinereous, 

 through all the intermediate shades, to black or dusky slate. 

 The .arboreal species are generally lighter colored than the 

 ground species, and have a more expanded creeping-disk. 

 The animals of P. arguta } annectens, turgida and attenuates, 

 have the ocular tentacles longer and more slender than the 

 other species, and the exudation of mucus is much more 

 copious and more viscid or tenacious than usual, resembling 

 in that respect the same difference as exists between the typi- 

 cal Helices and the arboreal Naninae." 



The pallial organs are characterized by the short, more 

 or less triangular kidney, -with a direct ureter which does not 

 extend to the 'Collar, and opens by a lateral pore. The peri- 

 cardium is as long as the kidney. The surface of the lung 

 shows no visible venation. It is densely peppered with 

 light dote (probably calcareous) arranged in irregular lon- 

 gitudinal lines. In P. arguta these light dots are present in 

 spots and stripes (pi. 42, fig. 4), but in other species examined 

 they are equally and densely spread over the whole surface. 



In P. rosea (pi. 42, fig. 5, x 3) the kidney is very short 

 and strictly triangular. According to Semper, that of P. 

 canalis seems to be of the same form. In P. arguta (pi. 42, 

 fig. 4) the kidney is relatively larger, and the pericardium 

 lies parallel to its longer axis. The ureter also is longer. 

 In an undetermined Raiatean species (doubtless of the re- 

 stricted section Partula) the kidney approaches the band- 

 like type (pi. 42, fig. 6), yet it is somewhat triangular, and 

 equal to the pericardium in length. This is probably the 

 prevalent shape of kidney, since Semper mentions that all 

 the species examined by him except canalis had the kidney, 

 "bandformig. " In most of the subgenera the kidney is 

 unknown. 



The alimentary canal is of the usual four-folded type. 

 There is a fusiform crop (pi. 42, fig. 5). 



The jaw is very thin and transparent, varying from slightly 

 arcuate to horseshoe-shaped, similar to that of Drymaus 

 and Zaplagius, formed by the union of many narrow delicate 



