DIDEMNUM GELATIXOSUM. 35 



[Canon A. M. Norman found a species in Parella 

 Bay, Guernsey, in 1865, which, judging from the 

 figure of it given by Alder (PI. LV, fig. 10), may be 

 the same as the above ; and another form which he 

 procured there at the same time (PI. LV, fig. 12) is 

 probably a variety.] 



Dr. Victor Carus (' Proc. Ashm. Soc.' II, p. 267) also 

 announces the occurrence of Didemnum <-<nttli<lnm Sav. 

 in the Scilly Islands, but as this is a Red Sea species 

 there may possibly be some mistake in its identity. 



[2. Didemnum candidum Savigny.] 

 (Figs. 104 and 105.) 



[Didemnum candidum SAVIGNY Mem. Anim. sans Vert, 

 pt, 2 (1816), pp. 14, 194, pi. iv, f. 3, and pi. xx, f. 1 ; 

 LAMOUROUX Exp. meth. Polyp. (1821), p. 75, pi. Ixxvii, 

 f. 7 ; FLEMING Philos. Zool. (1& 22 )< II, p. 515; EICHWALD 

 Zool. Spec. I (1829), p. 268 ; FLEMING Moll. Anim. (1837), 

 p. 213 ; DELLE CHIAJE Descriz. Anim. Invert. Ill (1841), 

 p. 21, pi. Ixxxv, f. 26; DESHAYES in Cuvier's Regne 

 Anim., Moll. (dr. 1845), pi. cxxix, f. 3; LOWIG & 

 KOLLIKER in Ann. Sci. Nat. (3), Zool. V (1846), p. 208, 

 pi. vi, if. 26, 27, and in Arch. Sci. Nat. Ill (1846), p. 297; 

 RUPERT JONES in Cyclop. Anat. IV, pt. 40 (1850), p. 1196, 

 f. 774 a; VICTOR CARUS in Proc. Ashmol. Soc. II (1851), 

 p. 268; SCHACHT in Archiv f. Anat. 1851, p. 192, and in 

 Quart. Journ. Micr. Sci. I (1853), p. 107; HOEVEN Handb. 

 Zool. (Engl. transl.) I (1856), p. 703 ; H. & A. ADAMS 

 Gen. Recent Moll. II (1858), pi. cxxxv, if. 3, 3 a ; OWEN 

 Moll, in Encycl. Brit. ed. 8, XV (1858), p. 332 ; BRONN 

 Thier-Reichs, III (1861), pp. 115, 117, pi. xii, f. 10. 



Didermum candidum DELLE CHIAJE Mem. Anim. senza Vert. 

 Ill (1828), p. 97, pi. xxxvi, f. 26. 



Eucalium candidnm LAMARCK Hist. nat. Anim. s. Vert. ed. 2, 

 III (1840), p. 493.] 



[Colony (fig. 104) incrusting, thin, opaque, and milk- 

 white in colour, flat or relieved here and there with a 

 few protuberances. Iinliriclnah (fig. 105) small, dis- 

 posed in fairly regular order throughout the mass, 

 their tunic membranous, marked with slender muscular 



