232 
marginibus quadratis, suturis nullis ; intus valvarum marginibus 
valde arcuatis, sinu lato, alto. 
Long. 1-05, lat. °8, alt. 24 poll. 
Hab. Monterey, cum precedentibus ; 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 110°), fusco-olivacea, jugo acuto; 
valvis intermediis lineis diagonalibus haud conspicuis; areis late- 
ralibus et valvis ultimis strigis radiantibus, areis centralibus 
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 ; ad jugum linea impressa. 
Long. 1°1, lat. 58, alt. +25 poll. 
Var. T. cerulea, 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 ; lineis diagonalibus vix monstranti- 
bus ; areis lateralibus et valvis ultimis tenuissime granulosis, gra- 
nulis longis, irregulariter radiantibus ; areis centralibus iisdem 
lineis longitudinalibus undatis instructis ; marginibus valvarum 
subquadratis, suturis parvis ; jugo acuto, mucrone inconspicuo ; 
limbo angusto, sublevi, tenui; intus virescente, valuarum 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. Curron ornatus, Nutt. MS. 
C. t. subrotundata, depressa (ad angulum 130°), fusco-olivacea, 
utraque parte jugi tenebrosius maculata; lineis diagonalibus, et 
in ultima valva lineis x. radiantibus, nodulis validis instructis ; 
areis lateralibus et valvis ultimis nodulis radiatim instructis ; 
areis centralibus lineis nodulosis longitudinalibus, vix undatis, 
interstitiis alte decussatis; valvarum marginibus subquadratis, 
