SuTER. — On New Zealand Polyplacophora. 



59 



A. 



Argosarchus horridus, White (1846). 

 spiniger, White, J ; B. filijormis, Colenso, ^ ; B. gerhardii, 



Kaup, 2 . 



This well-known species was represented in the collection 

 from the Great Barrier Island by one male and one female, 

 which have the following dimensions : Length of the body, 

 5 128mm., <J 95mm.; of mesothorax, 2 28mm., J 21mm.; of 

 metathorax, 2 25 mm., ^ 19 mm. ; of abdomen, J 64 mm., 

 ^ 49 mm. ; of antennae, ? 29 mm., <? 29 mm. ; of anterior 

 ■femur, $ 36 mm., <? 24 mm. ; of middle femur, 5 26 mm., 

 ^ 20 mm.; of posterior feumr, $ 26 mm., S' 19 mm. The 

 bases of all the femora are pale in colour, more broadly so 

 in the male than in the female. 



It is found throughout New Zealand, as far south as the 

 West Coast Sounds of Otago. 



Lepidopleurus. 



Art. VI. — Netv Zealand Polyplacophora : Keys to Genera and 



Species. 



By Henry Suter. 



IBead before the Philosophical Institute of Canterbury, 2nd November, 



1898.] 



Key to Genera. 



A. Valves lacking insertion plates . . 

 AA. Valves possessing insertion plates, valves i.-vii. or 

 i.-viii. having slits ; teeth smooth or but 

 slightly roughened between the slits, never 

 closely, fiuely 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 tegmentura ; 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 (>iugle in one 

 species), girdle with compact 

 diamond-patterned covering ; gills 

 as long as the foot 

 DD. Valves solid at eaves, girdle densely 

 covered with fidt imbricating 

 scales, side-slits single . . 



Gallochiton. 



Ischnochiton. 



