145 



M. Rang further observes that this curious and very incompletely 

 known genus only contains a single species, which is found in the 

 Mediterranean Sea ; and he adds that he only knowa it by a drawing 

 communicated to him by Cuvier, who remarks (' Regne Animal') that 

 in the figure given by M. De Blainville (' Malacologie,' xlvi. 3) the 

 animal is placed in the shell the wrong way ("en sens contraire du 

 veritable"), and that his (Cuvier's) description rests on recent and 

 repeated observations made by M. Laurillard. M. Deshayes confirms 

 this remark as to the inverse position of the animal, and says that he 

 has had occasion to verify it often. 



M. Rang in 1829 knew but one species. M. Deshayes, in his 

 edition of Lamarck (1836), enumerates five. The species known to 

 M. Rang must have been Cymbulia Peronii. 



Limacina {Spiratella, De BL). Animal elongated anteriorly, turned 

 into a spiral form behind ; branchiae in the form of plaits on the back ; 

 mouth furnished with two small appendages, which are united by one 

 of their extremities to the anterior border. 



Shell very delicate, fragile, vitreous, spiral, not carinated, turning 

 rather obliquely on itself, with a circular aperture and simple borders. 

 (Rang.) 



Curier is of opinion that the Limacince ought, according to the 

 description of Fabricius, to bear a strong relationship to Pneumoder- 

 mon ; but their body is terminated by a tail, which is twisted spirally 

 (" contour-ne'e en spirale"), and is lodged in a very delicate shell, of 

 one whorl and a half, umbilicated on one side and flattened on the 

 other. Cuvier adds that the animal uses its shell as a boat and its 

 wings as oars when it would swim on the surface of the sea. The 

 same author remarks, that the only species, Clio htlicina of Phipps 

 and Gmelin, is scarcely less abundant in the icy sea than Clio borealit 

 [CLIO], and is considered as one of the principal aliments of the whale. 

 He observes that he does not know whether the animal figured by 

 Mr. Scoresby, of which M. De Blainville (' Malacologie,' pi. xlviii. bis, 

 f. 5) makes his genus Spiratella, is in reality, as M. De Blainville 

 believes, the same animal with that of Phipps and Fabricius. M. Rang 

 considers Spiratclla of M. De Blainville as synonymous with Limacina, 

 of which M. Rang states that but one species is known, and says that 

 it would be interesting to have new accounts of it. He speaks of its 

 inhabiting the North Sea, its prodigious abundance, and the possi- 

 bility of its serving as food for the whales. Phipps mentions it as 

 being found in innumerable quantities in the arctic seas, and describes 

 its body as of the size of a pea, rolled up into a spire like a helix, and 

 its ovate, obtuse, expanded wings as being greater than the body. 

 The following cut is taken from th figure of M. De Blainville, who 

 founds his genus (which he places under his family of Pteropoda, 

 between Atlanta and Argonauta) on the materials furnished by 

 the Rev. Dr. Scoresby, and considers his Spiratella as synonymous 

 with Cuvier's Limacina. 



Spiratella Limacina of De Blainville. 



Mr. O. B. Sowerby gives a figure of a Limacina (' Genera of Recent 

 and Fossil Shells,' in the same number as that which contains 

 Cymbulia) from Messina. He describes it as a thin, fragile, spiral, 

 discoid shell, nmbilicated on both sides, and carinated on the back 

 and below, with a membranaceous lamellar keel, and he says that it 

 has externally much the appearance of a very diminutive umbilicated 

 Nautilia. 



M. Deshayes, in his edition of Lamarck, remarks that the Limacina, 

 of which M. De Blainville formed his genus fZpiratelta, have in fact 

 much analogy with the Cleodora ; and that they are CUodora whose 

 shell is spiral, and not swimming Gastropods, like the Cannarue and 

 Atlanta. M. Deshayes goes on to state that he has many individuals 

 preserved in spirit, which he owes to the generosity of Dr. Fleming, 

 that he has examined them with attention, and that they have not 

 the projecting foot of Atlanta, nor a fin-like foot, but two lateral 

 fins of the form of those of the Cleodorai. He adds that they have no 

 tentacles, and no eyes, but a mouth in the shape of a triangular slit at 

 the summit of the angle which forms the fins. The shell is not 

 closed by an operculum as that of Atlanta is. The anus and the 

 organs of generation have their issue from the right side, below the 

 fin and at its base. M. Deshayes is of opinion that the genus ought 

 to remain among the Pteropods, where it was placed by Cuvier and 

 Lamarck. 



Spiralii. Shell thin, transparent, of several spiral whorls, coiled to 

 the left, spire elevated or depressed, surface smooth or reticulated, 

 mouth anirulated below or canaliculated, sometimes prolonged into a 

 spine-like curved beak. Animal elongated, spiral ; head not distinct; two 

 fin-like expansions united at their base by an intermediate lobe bearing 

 an opercnliim ; branchiae in a cavity formed by the mantle. Operculum 

 vitreous, very thin and transparent, of few whorls. 



This genus was constituted by the naturalists attached to the 

 exploring ship Bonite, for some very small Pteropoda they met with 



HAT. HIST. DIV. VOL. III. 



during their voyage. They are distributed through all seas, and 

 are equally present in the Atlantic, the Indian, and Pacific Oceans. 

 Three species of tnis germs have been recorded as British, S. Flemingii, 

 S. Mac Andrei, and S. Jcffreytii. They are all very rare. 



Hyalcea. Animal glooular or oblong, furnished with two lateral 

 expansions more or less elongated backwards ; the intermediate lobe 

 of a demi-circular form ; two very short tentacles, hardly distinct, 

 contained in a cylindrical sheath ; the aperture of the mouth provided 

 with two labial appendages ; orifice of the anus at the right side of 

 the mantle ; that of the male organ in front and within the right 

 tentacle ; that of the female organ on the same side, at the point of 

 separation of the two parts of the body ; branchiae pectinated on each 

 side in a particular cavity. 



Shell horny or vitreous, transparent and fragile, in form of a slipper, 

 straight or recurved, with an anterior opening, and split laterally, 

 tricuspidated backwards. (Rang.) 



M. Rang remarks that this beautiful and interesting genus, the 

 anatomy of which has been made known by M. Cuvier and M. DC 

 Blainville, is perfectly distinct from those which approach it. He 

 speaks of the Hyalcece as very 'small animals, spread over all the seas 

 of the torrid zone and a great part of those of the temperate zones, 

 and of the occurrence of the same species on the most opposite points 

 of the globe. He adds that the discovery which he had made of many 

 species, one in a fossil state, had caused him to divide the ffyalace 

 into the two following groups : 1. Globuloste, Shell subglobular, 

 having the lateral slits nearly as long as itself, and the appendages 

 placed very much backward. H. uncinata, &c. This group, he says, 

 is the most numerous. 2. Elongatce. Shell elongated, having the 

 lateral slits short and the appendages advanced. H. trispinosa, &c. 



He states that at the time he wrote five species completed the 

 group, and gives the following figure of a Hyalosa,. 



Ifyalaa. 



a, flns ; I, intermediate lobe ; c, mouth ; t, lateral expansions of the mantle ; 

 t, viscera, seen through the shell; A, the shell. 



Cuvier describes Hyalasa as having two great wings, no tentacles, a 

 mantle slit at the sides, lodging the branchiso in the bottom of the 

 fissures, ami covered by a shell equally slit at the sides, the ventral 

 surface of which is very convex, the dorsal flat and longer than the 

 other, and the transversal line which unites them behind furnished 

 with three pointed dentilations. In the living state, the animal pro- 

 jects by the lateral slits of the shell filaments more or less long, which 

 are productions of the mantle. Cuvier concludes by observing that 

 the species most known (Anomia tridentata, Forakahl; Carolina 

 natans, Abildgaardt; Ilyalaea cornea (tridentata), Lamarck) has a 

 small yellowish demi-transparent shell, which is found in the Medi- 

 terranean Sea and in the ocean. 



V, J 



Hyaloid tridentata. 

 a, the anterior border, showing the mouth. 



M. De Blainville; who has published a monograph of this genus in 

 the ' Journal de Physique ' and in the ' Dictiounaire des Sciences 

 Naturelles,' states that it contained at that time (1825) from five to six 

 species, all of which appear to be the inhabitants of warm climates. 

 He considers the genus Glandiolui of De Montfort as belonging to the 

 Hyakea, and quotes the observation of M. Defrance to that effect with 

 approbation. 



M. Deshayes in his edition of Lamarck (1836) observes, that in the 

 comparison which the latter makes of the Ilyalane with the Conchi- 

 fers, he had remarked that they approached so closely that he had 

 found it proper to place the Uyalceas at the head of the Mollusks. 

 Lamarck had suffered himself to be seduced by an analogy rather 

 apparent than real. It is not with the Lamellibranchiate Conchifers, 

 continues M. Deshayes, that the HyalaxR should bo compared, but 



