342 MOLLUSCA. 



S. pelagica, L.; Cuv., Ann. du Mus., VI, Ixi, 1, 3, 4. Com- 

 mon on the floaiing fucus of almost every sea. 



Glaucus, Forster. 



Body elongated; orifices of the anus and of the genital organs as in 

 the preceding; four very small conical tentacula, and on each side 

 three branchiae, each of which are formed of long slips arranged 

 like the sticks of a fan, which also aid them in swimming. They 

 are beautiful little animals, that inhabit the Mediterranean and the 

 Atlantic, prettily coloured Avith blue and nacre; they swim on their 

 back with great swiftness. Their anatomical structure is very simi- 

 lar to that of the Tritonia, but the species are not yet well ascer- 

 tained(l). 



Laniogerus, Blainv. 



Two series, on each side, of small and finely pectinated laminae, 

 which are the branchiae; the body shorter and thicker than that of a 

 Glaucus, but there are four small similar tentacula(2). 



Eolidia, Cuv. 



Resembles a small Limaxin form; four tentacula above, and two on 

 the sides of the mouth; the branchiae composed of laminae, arranged 

 like scales, mere or less crowded, on each side of the back. Found 

 in every sea(3). 



Cavolina, Brug., 



The tentacula of the Eolidiae, with retiform branchiae, arranged in 

 transverse rows on the back(4). 



(1) Doris radiata, Gm., Dup., Phil. Trans., LIII, pi. iii; — SeylUt macrSt, Bosc, 

 Hist, des Vers; — Glaucus atlanticus, Blumenb., fig"., Nat. Hist., pi. 48, and Manuel., 

 fr. trans., II, p. 22; Cuv., Ann. du Mus., VI, Ixi, ii, F^ron, Ann. Mus. XV, 

 iii, 9. 



(2) Laniogeriis Elfortii, Blainv., Malac.,pl. xlvi, f. 4. 



(3) Doris papulosa, Zool. Dan., CXLIX, 1 — 4; — Doris bodoensis, Gunner., Act. 

 Hafn., X, 170; — Do7-is minima, Forsk., Ic, xxvi, H; — Doris fasciculata. Id., lb., 

 G; — Doris branchialis, Zool. Dan. CXLIX, 5 — 7; — Doris coerti lea, Lin. Trans., VII, 

 vii, 84;— Eolidia histrix. Otto., Nov. Act. Nat. Cur., XI, xxxviii, 2, &.c. 



(4) Doris peregrina, Gm., C^avolini, Polyp. Mar., VII, 3; — Eolidia annulicornis, 

 Chamisso, Nov. Act. Nat. Cur., XI, part II, pi. xxiv, f. 1; — Doris longicornis, Lin. 

 Trans., IX, vii, 114? 



N.B. This genus must not be confounded with the Cavolina of Abildgard, 

 which is the Hyalaeu. 



