80 S. LOVEX, ON I'OLRTALESIA, A GENUS OF ECHINOIDEA. 



The calyc'iiial system oF tlic Pourtalesiada? is much more anomalous, and at the 

 same time not a little unsettled. In tlie specimen of I'ourtalesia Jeft'reysi, iV. 7, y/V/. /, 

 the calycinal system is brought out of contact with the interradia 1 and 4 through 

 the interjaeence of the detached plates of 5. Its general form is that of an irregular 

 pentagon. Its constituents are all coalesced into one ])iece, the madreporal filter spread- 

 ing its pores oxer its central forepart. The radials are not to be distinguished. The 

 four sexual apertures are displaced, not answering to their res[)ective interradia, moved 

 forward, those of 2 and 3 being near the ambulacrum III, and those of 1 and 4 almost 

 opposite the II and IV. Another specimen, PL V, jh/. 27, 28, 29, not very different 

 from the first, iias the madreporic filter occupying the hinder part of the central space, 

 the anterior pair of sexual pores nearly answering to the interradials 2 and 3, the 

 posterior being pressed forward so as to front the an)bulacra II and IV. An impres- 

 sion, not unlike an orbit, near the end of ambulacrum III, pg. 29, possibly indicates 

 the existence of a radial. In a third specimen. PL V, fig. 25, 26, the disordered con- 

 dition of the system is still more obvious. The costals 1 and 4, separated from the 

 rest by distinct sutures, adjoin the ambulacra II and IV, and are driven widely apart 

 by an advanced plate of .'). 



In Pourtalesia laguncuhi, PL Vll, jig- 52, much tlie same holds good. There are 

 no traces of radials. The costals I and 4, bounded l)y distinct sutures, adjoin the 

 ambulacra II and IV, tlie costal 1 being partly in contact with the interradial 1 /^ 

 there being only one advanced plate of 5, and that intervening between the costal 4 

 and the interradial 4 n. The sexual pores of the costals 2 and 3 nearly answer to 

 their respective interradi;i. The madreporic filter occupies the central space. 



In Pourtalesia ceratopyga, PL VI f, fig. 51, the water- filter spreads over the greater 

 portion of the system, partly to its outermost margins. The costal 1 is completely 

 united to the rest, but on the left side the costal 4 is Avholly separated, by the inter- 

 position of three plates detached from the interradium 5, and both costals adjoin the 

 ambulacra II and IV, while the hind margin of the system is contiguous to the inter- 

 radials 1 b and 4 a. The biviary ambulacra I and V, as in the foregoing species, 

 terminate dorsally far apart from the calyx, and without any ti-ace of radials. 



The calycinal system of Echinocrepis cuneata, PL Vll, fig. 54, is an irregular 

 pentagon. The madreporite spreads nearly over the whole, excepting the costals 1, 3 

 and 4, which are however completely united to the rest, provided with sexual pores 

 and not much displaced. The costal 2 is completely invaded by the filter, some of 

 whose pores are seen on its very edge, even in the suture. The radials II, III, W 

 are absent, but tlie I and V very distinct, of a fair size, pentagonally lengthened, con- 

 tiguous to each other as in the Ethmophract Spatangi, and to tlie terminations of the 

 ambulacra I and V. They seem to bear eye-spots. 



Thus in Echinocrepis the calycinal system still presents somewhat of a ^patangoid 

 character, such as this is exhibited by Palajotropus and Pala^ostoma, in the dispo- 

 sition of the water-pores and the obliteration of the sutures, while, at the same time, 

 another feature peculiar to the older meml)ers of the grou]) '), the contiguity of the 

 ') Conip. Ecliinoconus coiiifus, Etudes, PI. X\ , fig. IIM. 



