336 HAWAIIAN AND OTHER PACIFIC ECHINI. 



GONIOPNEUSTES. 



Duncan, 1889. Joum. Linn. Soc. London. Zool., XXIII, p. 113. 

 Type-species, Amblypneusles penlagonus A. Agassiz, 1872. Bull. M. C. Z., Ill, p. 56. 



There can be no doubt that Duncan was quite right in instituting a new 

 genus for the remarkable and apparently very rare sea-urchin, which A. Agassiz 

 described in 1872 as an Amblypneustes from Mauritius. The abactinal system 

 with oculars I and V fully insert, the high coronal plates, the presence of scattered 

 plates on the buccal membrane, the scarcity of spines and the large size of the 

 primaries combine to make the genus unusually well characterized. The tj^pe 

 and only known species was based on a single specimen, in the M. C. Z. collec- 

 tion, and figured in the Revision. (Since the text states correctly the measure- 

 ments of the specimen as 22 X 21.5 mm. while the figures on PI. Vlir measure 

 32 X 30 mm., it is evident that the "explanation of the plate" is erroneous in 

 saying the figures are natural size.) The locality, whence this specimen came, 

 is very doubtful. It was purcha.sed in Hamburg in 1870 and bears the label 

 "Brandt. Haml)urg." It is entered in the IM. C. Z. catalogue as from "He de 

 France?" So far as known, no other specimens are to be found in mu.seums, 

 and neither Pike nor Mobius, nor Robillard in their extensive collecting at 

 Mauritius ever met with this remarkable echinoid. It is most probable that the 

 specimen came from Australia. 



Goniopneustes pentagonus Duncan. 



Amblypneustes pentagonus \. .\p.i.ssiz, 1872. Hull. M. C. Z., Ill, p. 56. 



Goniopneustes pentagonus Duncan, 1889. Joum. Linn. Soc. London. Zool., XX 111, p. 113. 



Plate 93, figs. 18-21. 



Ill :i(i(iiti()ii (o the characters given in the "Revision." the following points 

 niMv l)c uuMitioiKHl. There are 18 intcrambulacral plate.-^ in each column and 

 (>;uii one bears a single, conspicuous, imperforate, non-crenulated tubercle. 

 There are also on eacii plate* a few (() in the mid-zone) well-'^paced secondaries, 

 and some very minute and widely scattered miliaries; the latter bear pedicellariae 

 but not .sj)ines. There are 43 anibulacral i)lates in each column but not more 

 than 12 15 carry jiriinarv tui>ercles: at the ambitus and below, every other 

 jilate has a luiiiiaiy but above the ambitus, there are very few indeed. There 



