M. A. Pomel on the Glassifioatwa of Echiuida. 227 



5. The Holasteria have the apex lengthened in conse- 

 quence of the intercalation of the ocellar pieces between the 

 genital pieces. The petals are still even with the test, with 

 the pores but slightly developed in most of them. Some 

 fascioles may be seen at the ambitus. In some the apex is 

 continuous {Holaster) ; in others it is disjointed, and there are, 

 as it were, two ambulacral summits (the sole genus is Meta- 

 porinus). 



The Ananchytida are divided into two groups : the first, 

 with the apex elongated, Offaster ; the second, with the apex 

 compact, Stenonia. 



The Lampadiformes are either edentate or furnished with 

 teeth. The former are divided into the Echinoneida^ with a 

 mouth without tubercle, or floscule, and with simple or sub- 

 petaloid ambulacra; and Gassidulida, furnished with a flos- 

 cule and tubercle at the mouth, and with petaloid ambulacra. 

 The second are divided into the Glypeastro'ida^ with petaloid 

 ambulacra, and the Echinoconida^ with simple ambulacra. 



The Echinoneida comprise three types : — 



1. The Dysasteria are still almost spatiform, and many 

 authors have united them with the Ananchytida ; but they 

 have the ambulacra of the Lampadifonnes on the inferior sur- 

 face ; their ambulacral summit is disjointed in the true Dys- 

 astery and simply elongated in Hyhoclyjpus. 



2. The Echinonea have the ambulacra simple and uniform 

 from the mouth to the apex, which is compact ; the peristome 

 is often oblique ; of fossil genera Pyrina may be cited. 



3. The Caratomia also have their apex compact, but 

 their ambulacra pass into the petaloid form ; they are almost 

 simple in Caratomis^ subpetaloid and unequal in Asterostomaj 

 and petaloid in Pygaulus. 



The Cassidulida are those of authors, less the Caratomia. 

 Some have a very rudimentary floscule between the cushions, 

 and the petals are dissimilar in Archiaria^ similar in Glypeus ,* 

 others have a well-developed floscule, with conjugated pores 

 in PyguriiSy non-conjugated pores in EcMnantlius 5 and a 

 fifth phyllodean type is remarkable on account of the short- 

 ness of the petals, Faujasiaj foreshadowing the following 



The Clypea^troida remain, divided into GlypeastreSj 8cutell(Bj 

 and Lagands. However, it would be perhaps convenient to 

 divide the last-mentioned group into true Lagance^ with a 

 buccal rosette and petaloid ambulacra, and Echinocyami with- 

 out buccal rosette, and with ambulacra hardly petaloid, and 

 formed of non-conjugate pores. 



The Echlnocomda are, again, those of authors, less the tooth- 



