1894.] NATURAL SCIENCES OF PHILADELPHIA. 211 



"series of twelve others rauging from 75 mm. dowu to 6 mm. in leiigtli. 

 The large ones are respectively 180 x 109 x 41 mm. and 130 x 109 x 

 84 mm., being both considerably flatter than the specimens described 

 by Mr. Pilsbry. 



' 'All my specimens are distinctly narrowed in front, and in this 

 particular the species differs essentially from P. patriarcha, which is 

 veiy round in outline. I have a specimen of patriarcha exactly the 

 same width as the two shells above mentioned, namely, 109 mm., 

 but its length is only 119 mm. Our species is further distinguished 

 by its sculpture from hoth pat r id re ha and mexicana — the ribs being 

 narrower and much more numerous than in patriarcha and decidedly 

 heavier than in mexicana. Every 5th or 6th rib in the adult shell 

 seems to be more prominent. ' ' ^ 



Dr. Wm. H. Dall's description of younger and less eroded exam- 

 ples than the types, here follows : — 



"Patella {Helcioniscus ?) kermadecensis. Soft parts unknown, but 

 the aspect of the shell is that of a Heldoniscus." 



"Shell large, depressed or only moderately elevated, porcellanous, 

 radiately sculptured, with the apex of the shell slightly anterior to 

 the center, erect, blunt (or eroded); color outside orange-yellow, 

 sometimes more or less scorched with purplish- black, obscurely con- 

 centric or radiating in its disposition, frequently asymmetrical ; in- 

 side polished opaque-white, cream color, or even orange color, with a 

 very narrow colored margin of orange, white, or black, following the 

 tint of the exterior ; the muscular impressions not polished, sometimes 

 darker orange than the rest, the enclosed area usually much the same 

 color as that outside the scars, but sometimes lighter or with faint 

 brown or flesh colored stains irregularly distributed ; muscular scars 

 catenate, not symmetrical, with about seven segments on each side ; 

 an obscure line, probably indicating the scope of the mantle is visi- 

 ble within the colored margin and this is emphasized to the left of 

 nnd in front of the head, where a strongly marked sinus extends to- 

 ward the apex close to and in front of the left arm of the pedal scar 

 and ceasing at the junction of the latter with the scar of the mantle 

 over the head ; this is distinctly indicated in all the specimens but is 

 less prominent in the younger specimens, and recalls the sinus of 

 Gadiniii though on a much larger scale; the margin of the shell is 

 rendered slightly irregular by the sculpture, and is, as usual, some- 



5 Nautilus, April, 1894, p. 142. 



