ECHINOIDEA. H. 



«3 



distinct calcareous cap in llic pciiul of tin- tuhc-tVcl (I'l. VII. Fig;. 17), though not formed hy one plate. 

 The spicules are of the usual form, hinj.;- in two close lon^^iludinal series. 



Ecliiiiocrcpis ciiiirata A. .■Xii'. In this species the bivial ambulacra are evidenth' uninlerru])ted 

 (vChall. -Ech. PI. XXXV. a. 10), as is also pointed out 1)\ de Meijere (sSiboga >-Hch. p. 168). In -Pan. 

 Deep-Sea Ech.' p. 147 Agassiz states that the arrangement of the actinal plates of Ecliiiiocrcpis 

 ati/infa is, according to Loven (Potirtalesia. PI. \'II. l'"ig. 53), much like that of Spatagocystis Clial- 



IcHgcri -> which seems to mean that the bivial andjulacra arc interrupted b\- the interambulacra i 



and 4. This can, Iiowever, not be deduced from the small fragment figured b\- Lo\en, and the figme 

 from the Chall. -Ech. quoted above does not seem to be so very incorrect, as it would be, in case 

 the species realh- agreed with Spatagocystis in this respect. Also Loven states expressly (p. 17) that 

 he considers EcJiiiiocr. cuiicata to differ in a marked manner from I'. Jiffrrysi. laguiicnla etc. in 

 having the bivial andnilacra uninterrupted. Uufortnuateh' the specimen in the IJritish .Museum does 

 not afford an\- solution of the question, the i)lastron not being preserved. The ajtical s\-stem ' is com- 

 pact, the postero-lateral (bivial) ambulacra not being separated from the rest of the apical system 

 through intercalated plates, as has been shown by Loven (On Pourlalesia. PI. \'I1. I'"ig. 54); I may 

 fiu'ther point out the fact that the dorsal plates of the odd interambulacrum are not paired, but alter- 

 nating (as seen in this same figure) evidentl\' a more primitive condition. Of pedicellarite 1 have seen 

 only one kind, viz. tridentate. The small ones are of the connnon sinqjle leafsliaped form, with the 

 apoph)sis continuing into the edges of the blade; the larger form is figured in the Challenger -Re- 

 port PI. XLV. Fig. 44, I have only to add that generalh' there is a wingshaped keel along the dorsal 

 side of the blade (PI. X. Fig. 39). The spicules are rather numerous, simple or triradiate. 



Ecliiiiocrcpis sctigcra A. Ag. differs from E. cuiicata in several important features. The bivial 

 ambulacra are interrupted on the actinal side by the postero-lateral interambulacra, and the apical 

 system is disconnected. I have found three kinds of pedicellari;e (on some small fragments examined in 

 the U. S. National Museum), \\v.. tridentate, rostrate and ophicephalous. The tridentate pedicellari;e are 

 of the common form, with simple leafsliaped valves (only a small specimen seen). The rostrate pedi- 

 cellaria; (PL X. P'ig. 12) are more or less elongate, the outer edge finely serrate (Perhaps this form is 

 not really the rostrate, but another kind of tridentate pedicellari;e) The ophicephalous pedicellarite 

 (PI. X. Figs. 3, 33) are somewhat smaller and more longstalked than usual; otherwise they do not differ 



■ Aga.ssiz (Panainic Ueep-Sea Ech. p. i;,i| says that the plates of the apical sy.steni of Bchinocripis are not as they 

 have been described by de Meijere; those of the bivium are well separated by the posterior lateral interambulacra from 

 those of the trivium. There are the two posterior ocular plates, and the anterior ones are ankylosed, the oculars of the tri- 

 viuni being lost and occupied by the madreporite. {Pis. 67. fig. 2 ; 6g, figs. 3, 4) ». Quite apart from the fact that Agassiz 

 here is in evident contradiction to his own statement (p. 146) that in Echinocrepis setigera the ocular plate can only be 

 traced in the odd anterior ambulacrum. In the crowding due to the intrusion of the intercalated and interambulacral plates 

 between the bivivim and the trivium they (— evidently the other ocular plates — ) have been pushed out of place or resorbed >, 

 it may be .stated that de Meijere's description (<:Siboga»-Ech. p. 162) is quite correct, his description being based on 

 Loven' s Figure 54. PI. VII (On Pourtalesia), as expressly named, and it is Echinocrepis cuncata whose apical system is 

 described, as is also expressly said, not E. sctigeya, to which Agassiz refers. Further de Meijere remarks (p. 164) «Nach 

 Agassiz' Figur (viz. PI. XIII. i of the Prelim. Report on the .\lbatross -Echinil scheiut die vou der . .Vlbatrossu-Expedition 

 erbeutete Echinocrepis scligera auch ein ebeiisolches, aus einander geriicktes Apicals3-stem zu besitzen, wie Spatagocystis u. s. w. 

 und wiirde sich somit von E. cuncata scharf unterscheiden . De Meijere's description of the plates of Echinocrepis is thus 

 quite correct. 



