150 HAWAIIAN AND OTHER PACIFIC ECHINI. 



These pedicellariae were all found on Mr. Agassiz's original material from near 

 Juan Fernandez in 65 fms. 



Nacospatangus depressus, sp. nov. 

 Plate 145, figs. 40-43. 



Length of test, 11.5 mm.; breadth at apical system, where it is widest, 

 8.75 mm.; height 5.25 mm., the greatest height being well back of the abac- 

 tinal system near the posterior end of the test. From the apical system the 

 test slopes forward at first gradually and then rather abruptly. The posterior 

 end of the test above the subanal plastron is vertical and is largely occupied 

 by the periproct, the plates of which carry a few minute pedicellariae but are 

 otherwise bare. The abactinal system is so compact I am unable to make 

 out the separate plates. The only genital pore is that in genital 3. The petals 

 are essentially as in N. gracilis so that Mr. Agassiz's figure (1904. Mem. 

 M. C. Z., 31, pi. 98, fig. 3) answers well for depressus in that particular, and in 

 the tuberculation also. Mr. Agassiz's figure 2 would answer for depressus 

 so far as arrangement of plates and tuberculation go, but in depressus the peri- 

 stome is shorter, wider, and less pentagonal, the labrum is longer (being broadly 

 in contact with the second ambulacral plate on each side) and the subanal 

 fasciole is wider and encloses an area which is almost circular (a bit pointed 

 on the side towards the mouth) and nearly or quite as long as wide. It should 

 be added, however, that this apparently great difference in the fasciole is not real, 

 but is due to foreshortening in Mr. Agassiz's figure. When specimens are com- 

 pared, the two species agree in the form of the fasciole. The sternum is some- 

 what flatter in depressus than in gracilis but the difference is not conspicuous. 

 The color (dry) is light wood-brown. 



The pedicellariae of depressus are characteristic. The tridentate arc 

 very scarce and small, with straight narrow valves (PI. 145, fig. 40) only .15- 

 .20 mm. long. The globiferous are common and have very large glands on the 

 small valves (PI. 145, figs. 41, 42), which are .15-. 20 mm. long. The teeth 

 around the terminal opening of the blade (PI. 145, fig. 43) are long and slender. 

 No triphyllous, rostrate, or ophicephalous pedicellariae were found, nor calcare- 

 ous particles in the tube-feet. 



While there is no doubt that this species is Dearly related to gracilis, the 

 differences in the shape of the test and in the globiferous and tridentate pedicel- 



