ORYFTOPLAX. 



In one (alcoholic) specimen before me, figured on pi. 11, figs. 37, 

 38, 39. pores are couipKt.lv absent. Figure 37 represents a portion 

 drawn from the edge of the ventral surface, which, though minutely 

 roughened is not spiculose. The figure is magnified 25 'diameter-. 



oumra Kve. PI. 8. fig. 14. 



" The variety gunnii, from South Australia and Tasmania, may be 

 recognized by the valves being narrower, with the exception of the 

 first, two. This form also appears to attain a larger size than spec- 

 - from New South Wales and other localities further north. A 

 specimen in spirit, from the mouth of the river Tamar, Tasmania, 

 presented to the British Museum by J. Macgillivray, exceeds four 

 inches in length. The mantle of the southern form also appears to 

 be rather less densely covered with the minute conical spines. The 

 number of gills on each side varies with age, and even in individual 

 specimens I have found 30 or 31 on each side in specimens of equal 

 size from both regions that is, north and south ; and in the largest 

 specimen before referred to there are 27 on the right side and 34 on 

 tin- left, and there is no appearance of any having been removed." 

 '/i.) 



C. BURROWI Smith. PI. 9, figs. 6, 7, 8, 9, 10. 



This curious species is known by the small size of the valves, the 

 remoteness from one another of the fourth, fifth and sixth, and the 

 excessively short and densely packed spines on the mantle. The 

 single specimen in spirit, from Port Molle, is of a buff color, 

 copiously mottled with green: this accords with a specimen (also in 

 .-pirit) mentioned by Reeve, collected by Capt Belcher in the Straits 

 <>f Macassar. The dried specimens are greyish, more or less rose- 

 tinted. The sculpture of the valves is very like that of C. ^riutu?, 

 consisting of a central smoothish ridge, with two or three finer and 

 more or less wrinkled ones on each side, the front valve of course 

 1'fin^r wrinkled throughout and lacking the central smooth ridge. 

 They are yellowish at the mucro or posteriorly, and pinkish red in 

 front. The plates of insertion are like those of C. striatus, and of a 

 pale greenish color. (Smith.) 



Chitonellu* burrowi has pores, and is therefore a ( :r>/j>fj>l<t.r. 



re is no trace of them externally, and they are only discernible 



by removing t r scaly coat ; they are then seen (but not dis- 



tinctly a> in the other species) upon the white skin beneath in just 



