324 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



The Tusia, Asteriua, Pavasteriua, both species of Echiiiaster, and the 

 Amphipholis are known only from the original specimens (all but one of 

 which were from Chile) and have not been met with by other collectors" 

 The Odontaster and Henricia are species of the far south and are in- 

 cluded in this list only because each has been reported once from north- 

 ern Chile, near Iquique ; their occurrence on the Peruvian coast is quite 

 unlikely. The Asterias and Amphiodia and both Cucumarias are Chi- 

 lean ispecies, which very probably occur, at least occasionally, in Peruvian 

 waters. Although there are specimens of Podophora in the M. C. Z. col- 

 lection labeled as from "Valparaiso" and "Callao," it seems extremely 

 improbable that these specimens were actually collected in South Amer- 

 ica, for the genus is a highly specialized one, characteristic of the Indo- 

 Pacihc region, and it could hardly have escaped the notice of such 

 collectors as Plate and Coker, if it occurred on the coasts of either Cliile 

 or Peru at the present day. It is clear, then, that the known Chilean 

 element in the Peruvian fauna is very small, and all of the species which 

 undoubtedly occur were taken by Dr. Coker, except an Echinaster and 

 a Cueumaria. South of Aguja Point, then, one may expect to find, in 

 suitable places, four species of starfish (Luidia hellonae, Asterina chi- 

 lensis, Stichaster aurantiacus, Heliastei' helianthus), one ophiuran {Ophiac- 

 tis krui/eri), four sea-urchins {Tetrapygus nitjer^ Arhacia spafulv/era, 

 StroiKjylocentrotus alhus, S. (jihhosus), and one holothuriau {Phyllophorus 

 perucianus). Korth of Aguja Point, however, one finds a much more 

 varied fauna and may reasonably expect ten or more species of starfishes, 

 (three species of Astropecten, two or three of Luidia, Xidorellia, Oreas- 

 ter, Paulia, Phataria, Pharia, Asterina, at least one Heliaster, and, possi- 

 bly, Stichaster), several ophiurans (Ophioderma, Ophiactis, Amphipholis 

 or Amphiodia, possibly Hemipholis, and two forms of Ophiothrix), eight 

 or ten sea-urchins (Tetrapygus, one or two species of Arbacia, Echino- 

 metra, Strongylocentrotus gibbosus, Encope, one or two Mellitas, Agassizia, 

 and perhaps Lovenia), and one or more holothurians (Thyone, Phyl- 

 lophorus, or Stichopus). 



Starfishes. Asteroidea. 



The starfishes comprise not only almost one half of all the echino- 

 derms known from the Peruvian region, but also the great majority of 

 the conspicuous or structurally interesting forms. More than half are 

 large species, reaching a diameter of over five inches, and several lauk 

 among the largest known starfishes. The twenty-five species represent 



