DISCIKA.. 145 



term used to express the same character. Thus the shells be^ ■ 

 longing to the family of AlatsB, in the system of Lamarck, are 

 ' diffuse in the outer lip. Fig, 402 to 406. 



DIGITATED. (Digitus, finger.) Branched out in long points, : 

 as E-icinula, fig. 413. 



DILATED. Expanded, spread. This term has the same applica- 

 tion as diffuse and alated, explained above. The outer lip of 

 Eostellaria Columbaria, fig. 403 (Hippochrenes, Montf.), will 

 serve as an example. 



DIMOEPHIl^A. D'Orb. A genus of microscopic Eoraminifera. 



DIMYAE/IA. (Aic, dis, double ; ixvov, myon, muscle.) The first 

 order of Conchifera, Lam. including those molluscs which have 

 • two adductor muscles, and consequently two muscular impres- 

 sions in each valve. The Conchifera Dimyaria are divided into 

 Crassipedes, Tenuipedes, Lamellipedes, and Ambiguse, fig. 44 

 to 155. 



DIODONTA. Deshayes. A genus formed for the reception of 

 Tellina fragilis. Hanley, in Sowerby's Thesaurus Conchylio- 

 rum. P. 319, pi. Ivi. fig. 14, and similar species, 



DIOICA. Bl. The first division of the class Paracephalophora, 

 Bl. It is divided into the orders Siphonobranchiata and Asi- 

 phonibranchiata, BL 



DIONE, A generic term used to distinguish the group of Oy- 



thersea represented by C. Dione. See Monograph of Cythersea, 



. No. 12, pi. cxxxii. fig. 98. Sowerby's Thesaurus Conchyliorum. 



DIPLODON. Spix. Hteia Syrmatophora, Lam. fig. 144, and 

 ■ Unio multistriatus, Lea, are doubtfully quoted by Lea as belong- 

 ing to this apparently ill-defined genus of ISTayades, 



DIPLODONTA. Brown. Eesembles Lfcika, but without the 



' ligneate elongation of the muscular impression. D. rotundata. 



Eorbes and Hanley, British MoUusca. Our figure, pi. xxvii. 



- fig. 576. . 



DIPSAS. Leach, 1817. A genus or sub-genus of Nayades, the 

 distinctive character of which is " having a linear tooth under 

 the dorsal edge." D. plicatus, pi. viii. fig. 142, 



DISCINA, Lam. Oebicula, Auct. 



