774 CLASS xiii. 



GEGENBAUER 1. 1. s. 210.] 



According to CANTRAINE it does not differ from the preceding genus, the 

 shell is cloven at the sides as in Hyalea, 1. 1. p. 23. 



Add genus Eurybia RANG Ann. des Sc. nat. xn. 328. 



Creseis BANG. Shell subulate, furnished with an orbicular 

 opening anteriorly, not cloven at the sides. Mantle not produced 

 at the sides. 



Comp. RANG Ann. des Sc. nat. xm. pp. 305 318. 



.ZVbfe. Here also or with the preceding genus is to be placed : 



Sub-genus Cuvieria RANG. See Ann. des Sc. nat. xn. p. 322, PI. 45 B, 

 figs. i8, V. BENEDEN 1. 1. PL 4 B. 



Spiratella BLAINV., Limacina Cuv. Body anteriorly auriculate 

 on both sides with a triangular pinna, posteriorly convolute. Shell 

 fragile, discoidal, on one side deeply umbilicate, on the other with a 

 spire slightly exsert. 



Sp. Spiratella arctica nob., Limacina kelicinalis LAM., BLAINV. Malac. PI. 

 48 bis, fig. 5, V. BENEDEN M6m. sur la Limacina arctica, M6m. de I' Ac. 

 royale de Brux. Tom. xiv. 1841, PI. 5. This little animal is very numerous 

 in the North Polar Sea, and serves the whale for food ; see O. FABKICIUS 

 Faun. Groenl. pp. 387 389, by which writer it is named Argonauta arc- 

 tica. In PHIPPS'S Voyage towards the N. Pole it is noticed under the name 

 of Clio helicina, and it is probable that CUVIER intended to name it Heli- 

 cina, a name which we should prefer to that of Limacina which perhaps 

 originated merely in a mistake. 



Cymbulia PERON. Animal included in shell, except two large 

 pinnae, confluent [partially, with a middle lobe that represents the 

 foot. GEGENB.]. Two contractile tentacles in front of mouth. 

 Shell hyaline, elongate, cymbiform, truncated posteriorly. 



Sp. Cymb. Peronii Cuv., P^BON Ann. du Mus. xv. PI. 3, pp. 10 12, 



Iconogr., Moll. PI. 4, fig. 2, V. BENEDEN Mem. de VAcad. de Brux. xn. 

 PI. i ; Mediter. Sea ; according to CANTRAINE these animals often lose their 

 shell. [The shell is formed within the mantle, and normally is covered by 

 a thin lamella of the same. This last is easily torn and thus perfect speci- 

 mens are rare : hence also the ease with which the animal loses its shell. 

 The shell has the consistence of soft cartilage and contains chitin. GEGEN- 

 BAUER I. 1. pp. 41, 42.] 



[Tiedemannia DELLE CHIAJE. Pinnae conjoined with the foot 

 to form an orbicular disc. - Mouth at the apex of a long proboscis, 

 very often bent backwards. Shell hyaline, gelatinous, slightly 

 excavated. 



