232 



maryinibus quadratis, suturis nullis ; intus valvurum marginibus 

 valde arcuatis, sinu lato, alto. 



Long. 1-05, lat. -8, alt. '24 poll. 



Hab. Monterey, cum prsecedentibus ; legit idem diligentissimus, 

 et olim, primus in eas oras perscrutator, clarissimus T. Nuttall. 

 Mus. Cuming et Nuttall. 



A small specimen in Mr. Cuming's collection was passed over as 

 the young of C. Hartwegii ; but a fine one in Mr. Nuttall's collection 

 distinctly displays the points of difference above indicated, which at 

 present appear of specific value. This specimen has much the ap- 

 pearance of a young Ch. articulatus, but differs essentially in the 

 character of the ligament. 



13. Chiton regularis. 



C. t. elongata, elevata (ad angulum 1 10°), fusco-olivacea.jugo acuto; 

 valvis intermediis Uneis diagonalibus huud conspicuis ; areis late- 

 ralibus et valvis ullimis strigis radiantibus, areis centrulibus 

 strigis longitudinalibus, parallelis ,• mucrone parvo; marginibus 

 valvarum subrotundatis, suturis modicis; limbo squamoso, squamis 

 oblongis, irregulariter tessellatis; intus valvarum marginibus haud 

 valde arcuatis, sinu lato, haud alto ; adjugum linea impressa. 



Long. 1-1, lat. -58, alt. -25 poll. 



Var. T. ccerulea, strigis prope marginem subgranulosis. 



Hab. Monterey; sub saxis legit — Hartweg. Mus. Cuming, 



A very similar species, but with larger scales on the margin, is 

 from New Zealand, and at present undescribed in the Cumingian 

 Collection. 



14. Chiton acutus. 



C. t. ovata, valde elevata (ad angulum 105°), tenui; olivacea, inter- 

 dum maculis tenebrosioribus ; Uneis diagonalibus vix monstranti- 

 bus ; areis lateralibus et valvis ultimis tenuissime granulosis, gra- 

 nulis longis, irregulariter radiantibus; areis centralibus iisdem 

 Uneis longitudinalibus undatis instructis ; marginibus valvarum 

 subquadratis, suturis parvis ; jugo acuto, mucrone inconspicuo ; 

 limbo angusto, sublcevi, tenui; intus virescente, valvarum margi- 

 nibus et jugo impresso albidis ; valvarum marginibus vix arcuatis, 

 sinu parvo, inciso. 



Long. *9, lat. - 5, alt. - 2 poll. 



Hab. Sta. Barbara: olim legit T. Nuttall. Mus. suo. 



A very sharply angled, thin, delicately marked species, with ex- 

 tremely thin margin, and the edges of the valves deeply cut within. 



15. Chiton ornatus, Nutt. MS. 



C. t. subrotundata, depressa (ad angulum 130°), fusco-olivacea, 

 utraque parte jugi tenebrosius maculata ; Uneis diagonalibus, et 

 in ultima valva Uneis x. radiantibus, nodulis validis instructis; 

 areis lateralibus et valvis ultimis nodulis radiatim instructis ; 

 areis centralibus Uneis nodulosis longitudinalibus, vix undatis, 

 interstitiis alte decussatis ; valvarum marginibus subquadratis, 



