THE VICTORIAN NATURALIST. 71 



differences are merely sexual, but is able to distinguish the two 

 on the form of the test and spines and the size and position of 

 the ovarian openings. The height of the test, however, is not 

 specific, as specimens in our collection show, and, as Agassiz 

 rejects the evidence of the spines, there remains only the size and 

 position of the ovarian openings. 



A study of the records of the distribution of the two species 

 shows, I think, that the discrepancies in them are due to a forced 

 attempt at species-making, and not to constant differences in the 

 objects themselves. Agassiz, in the Challenger volume, records 

 G. geranioides from East Indies, Australia, and Tasmania, and 

 G. tubaria from Australia, Tasmania, and New South Wales (sic). 

 He says, also, that a large number of specimens of G. tubaria were 

 dredged outside Port Phillip Heads and off East Moncoeur 

 Island, near Wilson's Promontory. G. geranioides does not 

 appear in the Challenger lists. Ramsay says G. geranioides is 

 not found in Port Jackson, while it is common on the south 

 coast. Port Phillip being, I think, intended. Tenison Woods 

 says it is found within the tropics, and is replaced in the south 

 by G. tubaria. Agassiz and Desor record G. geranioides from 

 Port Western, New Ireland, and New Holland (I suppose the 

 New Ireland record is responsible for the " East Indies " of 

 Agassiz). M'Coy says both species are common with us. 



I am unable to see more than one species in the material I 

 have examined. 



Lac. — The best specimens I have seen were dredged about 

 Port Phillip Heads by the late J- Bracebridge Wilson in 10-40 

 fathoms. Bottom bhelly sand, It also occurs in Western Port 

 (Gabriel). It is very rarely washed up on the beach. 



2. Strongylocentrotus erythrogrammus, Val. 



This is one of our commonest Urchins on a rocky bottom, and 

 extends from tide mark to over 30 fathoms. We have no Victorian 

 form that can be confused with it. 



The species is found in Australia, Tasmania, New Caledonia, 

 Samoa, and New Zealand. The genus is world-wide and outside 

 Australia ranges back to the Miocene. 



3. MiCROCYPHUS ZIGZAG, L. Ag. 



This species has much the build of the last one, but the pre- 

 sence of a zigzag bare area, usually coloured reddish-brown, on 

 the median part of both ambulacra and interambulacra serves 

 as one of several important distinguishing marks. 



Our examples are all small. The species has a wide range : 

 Japan, Philippines, Southern Australia, Tasmania. The Challenger 

 dredged it off Port Phillip Heads in 38 fathoms, and off East 

 Moncoeur Island in 40 fathoms, both on a shelly sand bottom. 

 Wilson's collections came from the Heads, and a depth of about 

 10 or 20 fathoms. 



