158 PKor. p. M. Duncan's revision or the 



Family Laganidje, (subfamily) A. Agassiz, Revision, 

 1872-74, p. 516. {Enlarged.) 



Test flat, with swollea or thin edges ; the petals more or less 

 unequal, narrow, lanceolate, moderate in length, ambulacra beyond 

 them very wide; pairs o£ pores for branchial tentacles few, and 

 between them are minute pores for prehensile tentacles, of which 

 there are also multitudes iu the interporiferous areas. Interradia 

 small, each with a single apical and peristomial plate, continuous. 

 Simple straight actinal grooves in the ambulacra, perforated, and 

 with a buccal process and buccal pores. Periproct between the 

 peristome and the posterior margin. Jaws small, rather high, the 

 teeth superior and slanting. Perignathie processes (ridges) single 

 on the interradial peristomial plates, situated so as to be beyond 

 and not below the jaws. Internal structure of several pillars 

 forming discontinuous concentric partitions close to the edge 

 of the test, and of partitions limiting the ambulacra. 



It is proposed to absorb the genus Rumpliia and the subgenus 



Feronella. 



Genus Laganum. 



Genus Laganum, Klein, 1734, Nat. Dlsp. Ecli. edit. Paris, 1754, 

 p. 92. Gray, 1825 (Lagana), Ann. Phil. n. s. vol. x. p. 427. 

 Agassiz, 1841, Monogr. d' Ech. viv. et foss. livr. 2, Les 

 Scutelles, p. 105. Gray, 1856, Cat. Bee. EcTi. Erit. Mus. 

 p. 8. A. Agassiz, 1873, Revision, p. 516. Loven, Etudes, 

 1874, pp. 47, 83. J. Bell, 1883, Ann. Mag. Nat. Hist. vol. 

 si. ser. 5, p. 130. Euncan, 1885, Journ. Linn. Soc., Zool. 

 vol. xiy. p. 206, pi. 31. {Amended.) 

 Syn. Rumphia, Desor, 1858 ; Polyaster, Michelin ; Michelinia, 

 Duj. ; Feronella, A. Agassiz. 



Test moderate in size and large ; subpentagonal or ovoid at 

 the swollen or thin margin, truncated posteriorly, longer than 

 broad, very depressed dorsally, flat or slightly concave actinally. 

 Apical system small, more or less stellate ; madreporite central, 

 with or without a curved furrow, into which enter a few water- 

 pores ; genital pores four or five, upon the flanks of the madre- 

 porite. 



Ambulacra much larger than the interradia, but with the 

 petaloid parts rather narrow, moderately long, nearly closed 

 didtally, plates simple ; poriferous zones with minute simple 

 pores in a transverse row between the consecutive large pairs ; 



