AGASSIZ: PRELIMINARY REPORT ON THE ECHINI. 77 
ECHINOTHURIDA, Wrv. THoms. 
Phormosoma panamensis A. Ac. 
The specimens of this species were all in a poor condition ; they are allied to 
Ph. tenuis, but this species is interesting in having on the actinal side the char- 
acters of Phormosoma most decidedly developed, while on the abactinal side the 
great elongation of the ambulacral plates and the arrangement of the coronal 
plates resemble the structural features of Asthenosoma. Better preserved 
specimens may show this species to belong to a new genus of the family 
intermediate between Phormosoma and Asthenosoma. 
Station No. 3374, southwest of Malpelo Island, in 1825 fathoms. 
Phormosoma hispidum A. Ac. 
Plate VI., Plate VII. 
This species is the Pacific representative of the Caribbean and Northern 
Atlantic Ph. uranus; it has like it an extensive geographical range, but in 
comparatively deeper water. The largest specimens collected measured 201 mm. 
in diameter. The test is marked for the great width of the ambulacral sys- 
tem at the ambitus, which is nearly as wide as the adjoining interambulacral 
system. The large primary radioles of the actinal edge are slightly curved and 
tipped. On the abactinal side of the ambitus the coronal plates both ambu- 
Jacral and interambulacral carry only one small secondary tubercle on the 
distal extremity of the plate with a few irregularly scattered miliaries. The 
outer primary row of interambulacral tubercles extends on half the coronal 
plates, the inner row only on two or three of them. 
PETALOSTICHA, HAk&ckKEL. 
SPATANGIDA, AaGass. 
POURTALESIA, A. Aa. 
Pourtalesia Tanneri A. Ac. 
Plate VIII. Figs. 1, 2. 
This species is closely allied to P. laguncula (Challenger Echini, Plate 
XXII Figs. 7-15, Plate XX XI. Figs. 1-11), but differs from it in the shape 
of the test, which is less bottle-shaped, the greater height of the anterior ex- 
tremity of the test, the concentration of the primary tubercles on the sides of 
the test in more or Jess parallel rows in a triangular space extending from the 
anal system to the lower angle of the ambitus, and the greater length of the 
