230 HAWAIIAN AND OTHER PACIFIC ECHINI. 



ferous were found but ophicephalous are abundant on posterior ventral ambu- 

 lacra; these valves are .22-30 mm. long besides the loop which is .06-. 12 mm. 

 more; in form they resemble those figured by Doderlein for G. valdiviae. The 

 rostrate pedicellariae are all of the ordinary type and the valves are about three 

 quarters of a millimeter long. The triphyllous are not peculiar; the valves 

 measure .11-. 12 mm. The tridentate show a very wide range of diversity in 

 size and form; the valves are .25-1.00 mm. long and have a very deep apophysis, 

 the larger the valve the deeper and more conspicuous the apophysis; the width 

 of the blade, which is dentate basally but becomes serrate distally, is from .20 

 to .40 of its length. 



This handsome Gymnopatagus is very well marked by the form and tuber- 

 culation of the test. The fine color of the young seems to be lost when the 

 animal is fully grown but it is even then a notably handsome spatangoid. It 

 is worthy of mention that the peripetalous fasciole is not , at all points, a single 

 band only. In the holotype, it forks where crossing ambulacrum III, an inner 

 branch running parallel to the main band for 8 or 9 mm.; there are also three 

 fragments of fasciolar bands in the same ambulacrum, 5, 6 and 9 mm. respec- 

 tively above the main band. In another individual, it is in interambulacrum 

 5 that the fasciole gives off a branch and in this case the branch is on the outer 

 gide of the main band, and runs across ambulacrum V, a distance of nearly 

 20 mm. from its starting point, at a distance of about 5 mm. from the main 

 fasciole. In a specimen about 62 mm. long, the fasciole is a complete, distinct 

 single band, while, as already mentioned in the smallest specimen it is very 

 narrow, not very distinct and incomplete. It is a fair deduction from these 

 facts to say that there is a steady growth of the fasciole and of accompanying 

 fasciolar bands from the time the individual is half grown. Probably very 

 young individuals would not be distinguishable from Maretia. 



Station 3810. Off Honolulu Light, Oahu, Hawaiian Islands. Bott. temp. 

 47.7°. 53-211 fms. Fne. co. s. 



Station 3811. Off Honolulu Light, Oahu, H. I. Bott. temp.'? 52-238 fms. 

 Co. s., r. 



Station 4045. Off Kawaihae Light, Hawaii, H. I. Bott. temp. 49°. 

 147-198 fms. Co. s., for. 



Bathymetrical range, 52-238 fms. Extremes of temperature. 49°-47.7°. 



Five specimens and a fragment. 



