37 



convex, pebble-like scales, which toward the outer edge are 

 subcarinated in the middle. Length 62, breadth 35 mill. 

 Port Jackson." 



Attention to the italicised words in the foregoing descrip- 

 tions will show the outside difference existing between these 

 two species, and a study of the specimens now at my com- 

 mand has satisfied me that the Tasmanian and South Aus- 

 tralian shells are identical, and are C. novcehollandia, Gray, 

 and not C. australis, Sowb., as given in Tenison Woods 

 Census of Tasmanian Marine Shells. Neither have C. con- 

 centricus, C. muricatus, or C. smaragdinus anything in common 

 with the present forms, as suggested by Mr. Woods, the 

 two former being true Chitons, and the latter a typical 

 Ischnochiton as restricted. The Port Jackson specimens are 

 typical australis in every particular. Of the Tasmanian 

 shells I have six, and of the South Australian I have examined 

 eight (a gradation of sizes in each case). In the most per- 

 fect of those from Tasmania there are superficial signs of the 

 longitudinal riblets on the central areas at the extreme sides 

 in front of the diagonal lines, as also are there on the two 

 largest of the South Australian ones. I do not note any con- 

 centric growth wrinkles on the C. australis from Port Jack- 

 son, but they seem to be more or less present in the C. novcz- 

 hollandicB from both localities mentioned, in which also the 

 radiating riblets of the terminal valves are more or less 

 broken up into concentric granulations. The two specimens 

 received from Mr. Sowerby are labelled "Australia," and 

 comprise one of each species. 



Quoy 



Moll. 



et 



Gaimard., Voy. de 



381, t. 74, f. 17-22 



1880, p. 111. 



Chiton pbllissbepentis 



1 Astrolabe, Zool. iii 



(1834), 

 C. fellisserpentis, Eeeve, Con. Icon., species 84. 

 Hutton, Cat, Mar. Moll, N.Z 

 " Shell oval, rather elevated, hardly carinated, the side 

 slopes somewhat convex. Surface lustreless. Colour a rather 

 dull and dingy olive or olive-green, marked with black along 

 the ridge, and on the sides of some valves. The lateral areas 

 moderately raised and sculptured with three or four rows of 

 distinct tubercles. Central areas having strong, irregular growth 

 wrinkles, and fine longitudinal riblets. Anterior valve larger 

 and much more elevated than the posterior, both being 

 sculptured with numerous regular rows of distinct tubercles, 

 the rows increasing by splitting. Posterior valve depressed, 

 the low mucro in front of the middle. Inside blue, in- 

 distinctly blotched with olive-green. Sutural plates rounded, 

 the sinus broad and deep, smooth or hardly denticulate. 



