Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 31, 1898
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Key to Genera.

A. Valves lacking insertion plates Lepidopleurus.
AA. Valves possessing insertion plates, valves i.-vii. or i.-viii. having slits; teeth smooth or but slightly roughened between the slits, never closely, finely pectinated; valves lacking eyes.
 B. Surface of intermediate valves divided into lateral and central areas by a diagonal (often indistinct) extending from beak to outer front angle of tegmentum; or, if this is not clearly the case, the posterior valve has an even, crescentic series of well-developed teeth; all valves having slits.
  C. Posterior valve having a crescentic series of well-developed teeth.
   D. Valves porous at the eaves. Sutural plates connected across the sinus, side-slits several (single in one species), girdle with compact diamond-patterned covering; gills as long as the foot Callochiton.
   DD. Valves solid at eaves, girdle densely covered with flat imbricating scales, side-slits single Ischnochiton.
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   CC. Posterior valve having a sinus behind, without slits; girdle hairy or nude, never scaly Plaxiphora.
  BB, Surface of intermediate valves divided into a narrow dorsal area and latero-pleural areas, the latter formed by the union of the lateral and the pleural areas; valves more or less covered by the naked spiculose or hairy (never scaly) girdle.
   C. Girdle provided with pores bearing tufts of bristles Acanthochites.
   CC. Girdle spongy, produced forward Spongiochiton.
AAA. All valves or valves i. to vii. possessing insertion plates cut into teeth by slits; the teeth sharply sculptured or “pectinated” outside by fine vertical grooves.
 B. Valves lacking eyes.
  C. Girdle scaly Chiton.
  CC. Girdle leathery, with short bristles Eudoxochiton.
 BB. Valves having eyes; posterior valve not deeply sinused behind, its insertion plate developed. Girdle covered with calcareous spines or spinelets Acanthopleura.
 BBB. Valves having eyes upon the lateral areas and head-valve. Insertion plate of tail-valve reduced to a smooth ledge or ridge, having no posterior sinus. Girdle leathery, microscopisally velvety Onithochiton.
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