MOLLUSCA. Tae 
Pterotrachea Forsx., Firola Bruc., Péiron. Body naked, elon- 
gate, with integument almost pellucid. Two eyes. Tentacles (very 
often) none. Head with a fleshy proboscis. Branchiz pinnate, 
free, at the posterior part of back. 
Sp. Plerotrachea coronata Forsk., Icon. rer. nat. Tab. 34, fig. A (copied in 
Encycl. méth., Vers. Pl. 88, Firola, fig. 1); in the Mediterranean. LEsEUER 
has given a monograph of this genus in the Jowrnal of the Philos. Soc. of 
Philadelphia, of which BLAINVILLE has made use in the article Firola, 
Dictionn. des Se. nat. Tom. xvit. pp. 62—68. Usually the tentacula are 
wanting. The species in which they are present were united by D’ORBIGNY 
under the name of Cerophora. Here belongs Fireola caudina Rane, 
GuéRIn Magas. de Zool. 1832, Cl. v. Pl. 3, Guirin Iconogr., Moll. Pl. 11, 
fig. 3 [For the Anat. and Hist. of Development, see GEGENB. 1. 1. pp. 
153—185, and Huxury 1.1. on the Anat. of Firoloides (Firola) 1. 1. pp. 
30—36. The auditory vesicle was shewn by LryDIG Anatomisch. Bemar- 
kung. ib. Carinaria, Firola und Aimphicora Zeitschr. fiir wissensch. Zool. 
III. 1851, p. 328.] 
According to D’ORpIGNY the singular genus Sagitta (see above, p.246) 
should be placed here. 
Carinaria. Body elongate. Head with two long, subulate ten- 
tacles, and two sessile eyes behind the base of tentacles. A small 
shell at the posterior part of back, thin, pellucid, conical, com- 
pressed, with apex turned backward. 
These animals have much resemblance to the preceding genus, and 
Cuvier at first thought that the Pterotrachee described by Forskit had 
only accidentally lost their shell. Mémoires, Moll. No. 18, p. 31. They 
differ, however, by the constant presence of two tentacles in front of the 
eyes and by small inequalities or tubercles on the skin. 
Sp. Carinaria cymbium (Argonauta Cymbium L.?) Ann. des Se. nat. XVI. 
Pl. 1, Gusérin Jconogr., Moll. Pl. 11, fig. 1, Pour Testac. utr. Sic. m1. 
Tab. 44, figs. :—11; in the Medit. Sea. Pott and DELLE CuIaJE gave an 
anatomical description of this animal (Zest. 111. pp. 26—35, and Memorie 
Sulla Storia e Notom. degli Anim. s. v.), which was afterwards completed 
by Mitnr EpwarpDs as to several remarkable peculiarities, Ann. des Sc. nat, 
sec. Sér. Tom. 18, Zool. pp. 323—329, Pl. x. fig. 3, Pl. x1. The remark 
of Linnaus, that the shell is not larger than a grain of sand, does not 
apply to this species, which therefore has also been often confounded with 
Carina vitrea, a larger species from the Indian Ocean ; Martini, Tab. 18, 
fig. 163, Buarnv. Malac. Pl. 47, fig. 3 a. 
Atlanta Lrsurur. Head furnished with a proboscis, two cy- 
lindrical tentacles, and two eyes. Foot compressed, acuminate 
towards the end, with a suctorial disc in the margin. Thin oper- 
culum, adhering to the ventral part below the foot. Shell very thin, 
involute, carinate. 
