ECHINOIDEA. II. 105 



of the test of this species. But it seems beyond doubt tliat in the iChallenger> Report two separate 

 forms were included under illcviiaster zonatus'-: one (St. 8), evidently the figured oiie, a trwe /feviias/er 

 and even the same as //. expergitus. the other (St. 126) probably a Schizaster, which will certainly 

 prove to be a new species. Tlie nanie Ilcniiastcr zoiiafiis ought then certainly to be dropped as a 

 synonym of H. expergitus. 



Hemiasfer Afc77lzi A. Ag. lias unfortunately not been figured by Professor Agassiz, and from 

 the description ( Blake>-Echini. jd. 66) it is quite impo.s.sible to see by which characters it is disting- 

 uished from H. expergitus, the only feature not agreeing very well with the latter species being the 

 '.narrow, comparatively elongate space included within the peripetalous fasciole . — From the U. S. 

 National Museum I have received for examination a large specimen of H. Meiitzi : it is certainly 

 identical with //. expergitus. Of course, I cannot statc with certainty that it is the true //. Mentzi. I 

 have seen; but I have no rea.son to doubt the Identification. Until the contrary is proved I must 

 then regard H. Alcutzi as a s\nou)in only of //. expergitus. — From //. gibbosus it is stated to differ 

 in having a larger nuniber of buccal piates, a feature which I do not find to hold good by comparing 

 the specimen of gibbosus from the <Siboga» with the specimen of //. Mentzi or with expergitus. 



Heniiaster ftorigerus Studer differs from expergitus in several respects, judging from the de- 

 scription and figui'es given by »Studer (Echinoidea d. Gazelle. (3S6) p. 8S2. Taf II. 3). The test is 

 broadest in the middle, not in the anterior end as in expergitus, and the lieight of the posterior end 

 is evidently .smaller than in the latter .species.' According to the description the anterior petals are 

 the shorter, but this is in contradiction to the figures 3 a and 3 c. The apical system, according to 

 the Fig. 3 d, is ethmolytic, a very important character, so important, indeed, that it must certainly 

 exclude the species from the genus Heniiaster. (Dr. M eis sner kindly informs me that Stnder's 

 description of the apical system is correct). The two anterior genital pores are 

 distinctly smaller than the posterior: in expergitus they are of equal size. The 

 relation of the labrum to the adjoining ambulacra cannot be seen from the figures; 

 but Dr. Meissner informs me that the labruni ends off the first ambulacral plate. 

 (Fig. 20). By a short examination of the type-specimen during a visit to the Berlin- 

 Museum I found two sorts of pedicellariæ, viz. tridentate and rostrate. The former 



' Fig. 20. Labrum and 



(PL XV. Fig. 23) are essentially like the large form of tridentate pedicellariæ in adjacent ambulacral 

 expergitus. but onl\- o-2"'"'. The rostrate pedicellariæ differ only very little from the jjoy^wms (From a 



form with the small end-part of expergitus. The sjiicules of the frontal tube-feet sketch by Dr. M. 



Meissner). 

 (PI. XV. Fig. 28) are more numerous, larger and more thorny than those of exper- 

 gitus. They are arranged in two close series; on one side those of both series have their ends inter- 

 mingled, on the other side they leave a bare space between them — just as has been described and 

 figured for Dorocidaris papillata (Part I. p. 33. PI. VIII. Fig. i). — That II. ftorigerus is a distinct species 

 is beyond doubt, but it is very doubtful if it eau remain in the genus Heniiaster. on account of its 

 ethmolytic apical system. However, as long as the species is so unsufficiently known it will scarcely 

 be possible to determine with certainty to which genus it ought to be referred. 



I Studer gives the foUowing nieasurenients: Length 24mm, Breadth 2111"'!^ Height 131""'. In //. cx/'fnri/ns of a corre- 

 sponding size the nieasurenients are: Lengtli 20™™, Breadth 20"'™, Height iS'S""". 



The Ingolf-Expedilion. IV. 2. 14 



