PARASTER SAVIGNYI. 171 



imperfectly known species, but we are still greatly in the dark in regard to 

 its growth-changes and the amount of individual diversity which may occur. 

 It is known as yet only from the Red Sea. 



Paraster rotundatus. 



Linthia rotundata Doderlein, 1906. Valdivia Ech., p. 249. 



This species is based on two specimens of small size from Chatham Island, 

 Galapagos. They have so little in common with Linthia australis, it is diffi- 

 cult to see why Doderlein placed them in that genus. On the other hand it 

 is not very easy to decide their generic affinities. The globiferous pedicellariae 

 are characteristic and unlike those of any of the species of Schizaster (sens, lat.), 

 but are much like those of Prymnaster, as figured by Koehler; their essential 

 structure, however, is not unlike that of the corresponding pedicellariae in 

 Paraster. There are four genital pores and the lateroanal fasciole is well 

 developed in the two specimens, so they may for the present be considered 

 Parasters. The relative importance to give in the Hemiasteridae to the num- 

 ber of genital pores, the presence or absence of a lateroanal fasciole, the struc- 

 ture of ambulacrum III and the character of the globiferous pedicellariae is 

 still undetermined, and until that is at least substantially settled the proper 

 generic position of this species must remain in doubt. 



Paraster savignyi. 



Schizaster savignyi Fourtau, 1904. Bull. Inst. Egypt., (4), 4, p. 436. 

 Schizaster (Paraster) savignyi Mortensen, 1907. Ingolf Ech., pt. 2, p. 122. 

 Paraster savignyi Koehler, 1914. Ech. Indian Mus. Spat., p. 172. 



In spite of Fourtau's opinion, I doubt whether this form, also from the 

 Red Sea, is anything more than a variety of the preceding, but having no evi- 

 dence, I defer to his assertion that it is distinct. There is in the M. C. Z. col- 

 lection a fine specimen of a Paraster labeled: "Schizaster jukesii Gray. Feejee 

 Islands. Godeffroy Mus. Orig. No. 6256." This specimen is 67 mm. long, 

 60 mm. wide and 42 mm. high. The apical system is 35 mm. from the anterior 

 end, and the test slopes markedly from it to the front. So far as I can see this 

 individual agrees well with Fourtau's and with Koehler's descriptions and 

 figures of savignyi. But the locality arouses suspicions. 



