64 HAWAIIAN AND OTHER PACIFK' ECHINI. 



genital pores. Glassy tubercles low and inconspicuous. Madreporic pore 

 small, not as large as male genital pore. 



The holotype and numerous other specimens in the M. C. Z. collection are 

 from Port Phillip, Victoria. All are bare tests and most of them are more or 

 less water worn. 



To the kindness of my friend, Dr. T. S. Hall of Melbourne, I owe the pri\i- 

 lege of describing this interesting new species. Several years ago he sent speci- 

 mens for identification, and when informed that they seemed to represent a new 

 species which he ought to describe, he generously sent many more specimens with 

 the statement that he wished me to do the describing. There is no doubt that 

 platytatus is quite distinct from any previously known species, and the sexual 

 dimorphism which it shows is most interesting, especially since it is an Australian 

 species of Fibularia which shows the only sexual dimorphism known in that 

 genus. The specimens of platytatus before me range from 2.7 mm. to 8 mm. in 

 length; the largest is 7 mm. wide and 1.8 mm. high. 



Echinocyamus incertus/ sp. nov. 

 Plate 128, figs. 1-3. 



Length 6 mm.; breadth not quite 5 mm.; height not quite 2 mm., mouth 

 about 1.2 mm. in diameter and periproct about .6 mm. Test moderately flat- 

 tened, narrowed anteriorly, not at all concave beneath, though there is a very 

 slight depression just back of the mouth. Petals evident but poorly formed and 

 with few pore-pairs, yet anterior petal has about four pore-pairs on each side. 

 Periproct much nearer to margin than to mouth. Genital pores much larger 

 than oculars. Radiating partitions within test (so far as can be seen through 

 mouth) fairly well developed. Auricles rather low and broad. Primary 

 tubercles about equal to genital pores. Glassy tubercles apparently wanting. 

 Madreporic pore much smaller than a genital pore. 



The holotype and only specimen is from Albatross Station 4045. Off 

 Kawaihae Light, Hawaii, Hawaiian Islands. Bott. temp., 49°. 147-198 fms. 

 Co. s., for. 



In the preliminary report on the Albatross Hawaiian Echini (1907, Bull. 

 M. C. Z., 50, p. 247) this specimen was listed as "Fibularia australis," but as 

 more detailed study has shown that there are no Fibularias in the collection, 

 the proper identification of this specimen has given some trouble. I have finally 



' inartus = dubious, in allusion to its doubtful status. 



