178 Transactions. 



Measurements : Holotype — length, 30 mm. ; breadth, 20 mm. The 

 largest paratype about 40 mm. by 30 mm. ; but it is rather contracted, 

 and therefore difficult to measure accurately. 



Material : The holotype. presented by Mr. A. E. Brookes to the 

 Dominion Museum, and four paratypes. 



Remarks. — Hitherto this species has been confused with Lorica volvox 

 (Reeve), though the resemblance is really only superficial, as careful 

 comparison shows several decided differences between the two species. 

 A study of figs. 2 and 5 on the accompanying plate reveals a striking- 

 difference in the general outline of the shells, Lorica haurakiensis having a 

 much steeper outline than Lorica volvox (Reeve). Figs. 3 and 6 show the 

 remarkable difference in sculpture of the second valve of each species, 

 fig. 3 (L. haurakiensis) exhibiting no trace of the nodulous sculpture so 

 characteristic of L. volvox (Reeve) (fig. 6) on the jugal tract. Also, the 

 lateral areas of L. haurakiensis are very much less nodulous than in 

 L. volvox. The pleural areas of the species differ in that L. haurakiensis 

 has the interstices of the longitudinal ribs smooth, while in L. volvox the 

 whole surface is rendered semi-nodulous by low heavy transverse corru- 

 gations. 



There are also differences in the girdle characters, the new species being 

 characterized by small close-set scales, and by the entire absence of the 

 tufts of transparent bristles, which are numerous on L. volvox. 



History. — In 1872 Hutton (4) described Chiton rudis from a specimen 

 in the Colonial Museum, and stated " Locality unknown." That specimen 

 has. since been identified at Chiton volvox Reeve (1847), now placed in the 

 genus Lorica. It is specifically inseparable from specimens presented by 

 Mr. C. Hedley. 



When inspecting the concrete sinker of the buoy off Whale Rock, 

 Bay of Islands, a few years ago, Captain Bollons obtained two or three 

 specimens, in about 20 fathoms, which the late Mr. Suter identified as 

 Lorica volvox (Reeve) (3). Since then Mr. A. E. Brookes has obtained 

 three more specimens off Kawau Island, Hauraki Gulf, in 20 fathoms, 

 and he has generously presented his largest specimen, the holotype, to 

 the Dominion Museum. There is a larger specimen, but his is the best 

 preserved. 



Careful comparison of the New Zealand specimens with C. rudis Hutton 

 and with authentic New South Wales specimens of L. volvox (Reeve) showed 

 C. rudis Hutton and the Australian specimens to be conspecific — indeed, 

 in all probability Hutton's type is an Australian shell — and showed that 

 the New Zealand specimens were a very distinct species not so far described. 



In the Manual of the New Zealand Mollusca, 1913, p. 46, pi. 2, fig. 22, 

 Suter records Lorica volvox (Reeve), giving C. rudis Hutton as a synonym, 

 but his accompanying description does not accurately fit either L. volvex 

 (Reeve) or L. haurakiensis, a specimen of which is in his collection. 

 Mr. Murdoch, of Wanganui, points out that the description appears to be 

 derived partly from his New Zealand specimen, partly from C. rudis, and 

 partly from Reeve's description. As we have no record of Lorica volvox 

 (Reeve) being obtained alive in New Zealand, and as the New Zealand 

 species is specifically very distinct, I would suggest that Lorica volvox 

 (Reeve) should be eliminated from our fauna, and Lorica haurakiensis take 

 its place as the New Zealand representative of the genus. 



An unfortunate numerical mistake has occurred on plate 2 of Suter's 

 Manual, where Lorica volvox is fig. 24, and Onithochiton undidatus is fig. 22. 



