34 HAWAIIAN AND OTHER PACIFIC ECHINI. 



millimeter long, but aborally two to three times that. Miliaries very slender, 

 not at all club shaped. Pedicellariae fairly common, but no triphyllous were 

 found. Ophicephalous have heads about .35 mm. long. Tridentate (PI. 124, 

 fig. 1) have heads about .70 mm. long, the blade of the valves abruptly expanded 

 near tip (PI. 124, fig. 3). 



Color dark yellowish brown, in the holotype, dried from alcohol. • A second 

 smaller specimen is bright reddish brown. 



The holotype is from Station 3962. 



The diff'erence in the shape of the test between this species and the next 

 is very noticeable. The absence of genital pores even in the larger specimen 

 shows that we have as yet only young individuals of lytopetalus. As genital 

 pores are present in specimens of reticulatus when they are 15 mm. long, or about 

 one third grown, it is possible the adult of lytopetalus reaches a length of at 

 least 100 mm. 



The Albatross took lytopetalus at the following places: — 



Station 3936. Off Laysan Island, Hawaiian Islands. Bott. temp. 68°. 

 79-130 fms. Sml. brk. sh., corln. 



Station 3962. Off Laysan Island, Hawaiian Islands, Bott. temp.? 16 

 fms. Wh. s., CO. 



Two specimens. 



Clypeaster reticulatus. 



Echinus reticulatus Linnr, 1758. Sys. Nat. ed. 10, p. 666. (pars). 

 Echinodiscus reticulatus Leske, 177S. .\dd. ad Klein, p. 143. 

 Clypeaster reticulatus Desmoulins. 18.37. Etude.s sur les Ech.: Tab. Syn. p. 214. 

 Clypeaster scutiformis Lamarck, 1810. Anim. sans Vert., 3, [>. 14. A. Agassiz, 1872. Rev. Eoli., 

 pt. 1, p. 101, i/ auct. seq. 



Plate 124, figs. 3-6. 



Although this is one of the best known species of the genus nothing has 

 hitherto been published concerning the spines and pedicellariae, except de Mei- 

 jere's account in his report on the Siboga Echini (1904). 'WTiile there is little 

 to add to that account, it is worth while to call attention to the variability of 

 the tridentate pedicellariae not only in size but in the shape of the valves. De 

 Meijere says the valves range from .075 to .375 mm.; those I have examined 

 range from .30 to .60 mm. In a .specimen from Reunion the blade is much 

 widened and rounded at tip (PL 124, fig. 3) but in a superb specimen from Mauri- 

 tius, it is less widened and is distinctly pointed (PI. 124, fig. 4)- In a young 



