g2 ECHINOIDEA. II. 



If we take these four groups to represent genera, or at least subgenera, which seems not at 

 all unreasonable, the latter group must keep the name Pourtalrsia. Of the names proposed by Pom el 

 two become svnonvms onl\- of Ponrtalcsia, \r/..- P/iyalopsis (for Idoiiiicula] and PJiyalc (iox Jeffrrysi]. 

 Only the name Ccratopliysa may be retained; P. rosra is named as the first species of this genus, but 

 the diagnosis is made from ceraiopyga. The latter species must then be taken as the genotype. For 

 the two other groups I ma\- propose the names: Hclgocystis and Echinosigra. 



The old genus Poiirtalcsia is thus divided into four genera (or subgenera), viz.: 



Helgocystis n. g. with the species carinata (A. Ag.). 



Echinosigra n. g. with the species phiale (W. Th.) (genot\pc) and parudoxa (j\Irtsn.). 

 Ceratophysa Pomel with the species ceratopyga (A. Ag.). 



Ponrfalrsia A. Ag. with the species miranda A. Ag. (genotxpe), Inguncitla A. Ag., Taiineri A. Ag., 

 Ji-ffrrys! W. Th., VVandeli Mrtsn. and hispida A. Ag. 



Perhaps the species Jcffreysi, Wandcli and hispida may yet prove to form a separate genus, 

 which would then get the name Phyalc Pomel; for the present, however, it seems not necessary to 

 separate these species from the genus Poiirtalcsia, though it must be conceded that they form a dis- 

 tinct group in that genus, differing from the other species in the shape of the test. P. Taiui, ri. how- 

 ever, is in some way intermediate between the two groups (by its narrow anal snout). That it should 

 be necessary to make /'. Iiispida the t\pe of a separate genus there is no reason to suppose. 



Spatagocystis Clialloigcri A. Ag. has been very carefully worked out, esi^ecially in the Pauamic 

 Deep-Sea Echini (p. 141), as regards the structure of the test. Three kinds of pedicellarise have been 

 figured in the ; Challenger »-Report (PI. XLII. 10—12 and XLV. 39—43), though ~ as is mosth- tlie 

 ca.se in that work — not mentioned in the text. I have found (on specimens examined in the liritish 

 Museum) two kinds of pedicellaripe, viz. trideutate and rostrate. Further I find in my preparation a 

 .single globiferous and an ophicephalons pedicellaria resembling exactly those of Urechinus Wyvillii. 

 As the specimens examined proceed from vSt. 147 from which station also Vrrcli. Wyvillii is recorded, 

 I think these pedicellarise do really belong to that species, having only accidentallN- got between those 

 of Spatagocystis. The tridentate pedicellarise are richly developed, occurring in at least two different 

 forms, viz. one with simply leafshaped, more or less slender valves with the apophysis continuing into 

 the edge of the blade (PI. X. Fig. 20 represents a small specimen of the .slender form; larger specimens 

 are rather similar to those of Erliivocrcpis cniicata)^ and another with rather short, broad vahes, nar- 

 rowed in the lower part of the hlaili- and terminating in a more or less i)roniiuenl hook (PI. X. I'^ig. id); 

 this is evidently the form figured in the Challengers-Report 1*1. XLII. 10 and PI. XL\'. 39— 40 as a 

 large-headed ': pedicellaria. I have not found so much meshwork in this as figured in the PI. XIv\'. 

 40 of the '(Challengers; there is often nothing at all. The form figured in PI. XLII. 12, evideutl> an- 

 other form of tridentate pedicellaria.-, I have not seen. The rostrate pedicellarice, figured as short- 

 headed, toothed, cup-pronged" pedicellarite (PI. XLII. 11 and XL\'. 41 and 43), are of a quite tvjncal 

 form, witli tiie outer edge of the rather .short and broad blade jjrovided with ca. 10-16 thick teeth 

 (PI. X. p-ig. 18); the edge of the ba.sal part is generally closely serrate, though not always .so regularly 

 as in the .specimen here figured. The stalk is more or less thorny (PI. X. F'i.g. 35). — There is a very 



