HAWAIIAN NESOPUPAE. 311 



specimens the presence of these two lamella? must be con- 

 sidered as a constant character. 



Two distinct forms of the angular lamella were found; in 

 the first this lamella is reduced to a nodular or a short 

 lamella-like form. This is usually united to the outer lip by 

 a thick callus sometimes of more than half its height. In 

 most cases it does not extend to the margin of the parietal 

 callus, while in others it not only reaches the margin but is 

 continuous with it, forming a low descending ridge along the 

 callus of the margin. In the second form the angular lamella 

 is discontinuous. It is represented by a low nodule seated 

 deep within and to the outside of the parietal lamella, followed 

 by a short interval with no indication of any thickening, and 

 terminating near the angle with the usual nodule, as in fig. 4&. 

 Forms with this character of the lamella are abundant in the 

 Pleistocene deposits on nearly all of the islands. 



The parietal lamella is always strong and usually slants 

 slightly outwards, but is often perpendicular to the parietal 

 wall ; in some cases the free margin is slightly sigmoid. The 

 infra-parietal lamella is usually represented by a low nodule- 

 like swelling, rather deeply seated. In a very few cases speci- 

 mens were found in which this lamella is discontinuous as 

 described in the case of the second form of the angular lamella. 

 The supra-columellar and subcolumellar lamellae are only pres- 

 ent in a few specimens. They are never lamelliform, but 

 appear as low callous swellings. The columellar lamella is 

 always strong, horizontally entering, and generally slanting 

 slightly downwards and emerging nearly to the outer margin 

 of the columella. In most cases it terminates rather abruptly 

 at the back and follows the margin of the columella upward 

 as a low thread-like swelling. In two races, one from Kauai 

 and the other from Oahu, the inner portion of this lamella 

 is turned abruptly downwards terminating at the base of the 

 columella, as in typical Nesopupa. The subcolumellar lamella, 

 when present, is usually represented by a low elongate swell- 

 ing parallel to the basal fold. The basal fold when present is 

 generally lamelliform and reaches about half the size of the 

 lower palatal. An infrapalatal fold is found only occasion- 



