THE ECHIN01DEA 321 



FAMILY 3. CASSIDDLIDAE. Asternata with closed, petaloid ambulacra 

 a floscelle is present. SUB-FAMILY 1. CLYPEIN A. Genera Clypeus, Leske ; 

 Clypeopygus and Faujasia, d'Orb. ; Pseudodesorella, Etallon ; Pygurostoma, 

 Cott. & Gauth. ; Pygurus, Ag. SUB-FAMILY 2. CASSIDULINAE. Genera 

 Australanthus, Bittner ; Breynella, Greg. ; Cassidulus, Lam. ; Eurhodia, 

 Archiac & Haime ; Paralampas, Dune. & Slad. ; Pygorhynchns, Ag. ; 

 Ehynchopygus, d'Orb. ; Stigmatopygus, d'Orb. S^J- FAMILY 3. CATO- 

 PYGINAE. Genera Catopygus, Ag. (Fig. XVI. 8) ; Neocatopygus, Dune. 

 & Slad. ; Phyllobrissus, Cott. ; Pseudocatopygus, Cott. & Gauth. ; Stu- 

 derui, Dune. SUB -FAMILY 4. ECHINOLAMPINAE. Genera Conolampas, 

 A. Ag. ; Echinolampas, Gray; Heteroclypeus, Cott.; Microlampas, Cott; 

 Craterolampas, Cott. ; Milletia, Dune. ; Neolarnpas, A. Ag. ; Oriolampas, 

 Munier-Chalmas ; Palaeolampas, Bell ; Phylloclypeus, Lor. ; Plesiolampas, 

 Dune. & Slad. ; Vologesia, Cott. & Gauth. SUB- FAMILY 5. EOLAM- 

 PINAE. Genera Archiacia, Ag. ; Asterostoma, Ag. ; Claviaster, d'Orb. ; 

 Eolampas, Dune. & Slad. 



SUB-ORDER 2. STERNATA. 



Atelostomata with the peristome eccentric anteriorly (usually bilabiate). 

 No floscelle ; anterior ambulacrum different from the rest. A sternum is 

 present. Fascicles sometimes present. 



FAMILY 1. COLLYRITIDAE. Sternata without floscelle. There is a 

 rudimentary meridosternum. The anterior ambulacrum is narrower 

 than the others. Apical system disjunct ; the three anterior ambulacra 

 grouped together as the "trivium," and the two postero - lateral am- 

 bulacra as the "bivium." There are no fascicles. Genera Collyrites, 

 Desmoulins ; Dysaster, Ag. (Fig. XVI. 6) ; Grasia and (?) Metaporhimis, 

 Michelin ; Pygorhytis, Pomel. Owing to the disjunct apical system, this 

 family has completely lost the radial symmetry, and presents some 

 remarkable resemblances to the Pourtalesiidae. It appears, however, 

 probable that while the Collyritidae have descended from some primitive 

 asternate form allied to Hyboclypus, the Pourtalesiidae are degenerate 

 forms of Prymnodesmian Sternata. 



FAMILY 2. ECHINOCORYTHIDAE. Meridosternous, labiate Sternata, with 

 an elongate apical system, and the ambulacra separated into a bivium 

 and trivium. Fascicles present in some genera. Genera Calymne, 

 Wyv. Thorns. ; Cardiaster, Forbes; Coraster, Cott. ; Cystechinus, A. Ag. ; 

 Echinocorys, Leske (syn. Ananchytes, Lam., Fig. XXXV. 2) ; Enallo- 

 pneustes, Pomel ; Enichaster, Lor. ; Entomaster, Gauth. ; Galeaster, Seunes ; 

 Guettaria, Gauth. ; Hagenovia, Dune. ; Hemipneustes, Ag. ; Holaster, Ag. 

 (sub -gen. Sternotaxisj Lamb.); Infulaster, Hagenow ; Jeronia, Seunes; 

 Lampadaster, Cott. ; Offaster, Desor ; Oolaster, Laube ; Ovulaster, Cott. ; 

 Stegaster, Pomel ; Stenonia, Desor ; Tholaster, Seunes ; Urechinus, A. Ag. 



FAMILY 3. SPATANGIDAE. Sternata with anterior ambulacrum re- 

 duced ; apical system compact ; sternum either amphisternous or merido- 

 sternous. SECTION 1. ADETINAE. Spatangidae without fascicles. Genera 

 Archaeopneustes, Greg. ; Clypeanthus, Cott. ; Echinocrepis, A. Ag. ; Enallaster, 

 d'Orb. (Fig. XVI. 7) ; Epiaster, d'Orb. ; Genicopatagus, A. Ag. ; Hemipatctgus, 

 Desor; Heterolampas, Cott.; Isaster, Desor ; Macraster, Roem. ; (?) Megalaster, 



