36 PROCEKIJINGS OF TUK MA LACO LOGICAL SGCIKXr. 



h;is more definitely sculptured lateral ai'cas, and is especially dis- 

 tingiiisliable from both /. crispus and /. longicymha by the extremely 

 minute girdle-scales. A similar, if not identical, species was found 

 by Mr. T. Iredale on Kaoiil or Sunday Island, Kermadec Group." 

 I regret that I cannot coincide with my friends' views in regarding 

 llie Kermadec shell as identical with the Norfolk Island species. 

 The differences in this group are slight, but I fortunately have scores 

 of each shell for comparison, and I find the Norfolk Island to be more 

 strongly sculptured, to be a longer, narrower, and higher shell, with 

 the back rounded and no keeling present. The girdle is also broader, 

 whilst the scales on the girdle of the Kermadec shell are even smaller 

 than those on the Norfolk Island one. The posterior valve in 

 I. intermedius has the mucro more central and more elevated, the 

 posterior slope being therefore shorter and steeper. Upon dissection 

 I find the posterior tooth of the insertion-plate of the median valves 

 to be very short, at once recalling that of /. niaorianus ( = /. longicymha, 

 auct.), and shorter, noticeably, than that of /. Jcermadecensin. I purpose 

 to have drawings of these valves made and published later. 



A species, somewhat familiar to me, with which Hedley & Hull 

 made no com{)arison, is luhnocMton gryei, Filhol {= fulvtis, Suter). 

 This shell is less elevated, has a less prominent posterior valve, and 

 larger girdle-scales. 



When Pilsbry separated the New Zealand and Australian species 

 of Ischnochiton, which had been previously confused under the 

 name /. longicymha, he restricted that name to the New Zealand 

 species, calling it /. longicymha (Quoy & Gaimard), and ignoring 

 Blainville's prior C. longicymha as indeterminable. Under the present 

 nomenclatural laws such action is inadmissible. Blainville's 

 C. longicymha was described from King Island, Bass Strait, and is 

 certainly not the New Zealand shell. Quoy & Gaimard simply used 

 Blainville's name, and did not separate the New Zealand species. 

 For this species, which is well described and figured in Pilsbry's 

 monograph (Man. Conch., vol. xiv, p. 87, pi. xxii, figs. 58-66, 1892), 

 I propose the name 



IsCHNOCniTON MAORIANUS, U.sp. 



This species differs from /. crispus (lleeve) in its larger size, more 

 rounded back, less distinctly striated girdle-scales, and the short 

 posterior tooth of the insertion-plates of the median valves. 



Hah. — Throughout New Zealand. 



Type from Otago Peninsula. 



IsCHNOCHITON KERM ADECENSIS, var. EXQDisrrus, var. iiov. PL I, Fig. 2. 



After much consideration I have concluded to introduce this shell 

 with varietal rank only. I collected a number of tliese shells and 

 found them to be fairly constant, but here accept their identity witli 

 the common Kermadec species. This variation seems unique in 

 Australasian Ischnochiton, as it does not occur in any other species to 

 mv knowledge, and I have seen nothing like it from Norfolk Island. 



