405 



LEPTOCLINUM. 



LEPTOPHINA. 



406 



Mediterranean. The Leptocephalus Morrisii is a small, slender, an 

 compressed animal, as thin as a piece of tape, and at first sigh 

 resembling a marine worm. The head is extremely small and shorl 

 the eyes large, the jaws furnished with numerous minute teeth ; th 

 pectoral fins and gill-openings very small, and the anal and dorsal fin 

 connected with the tail. The outline of the body resembles that o 

 the Lancelot (Branchiostoma) ; but the organisation of the Leploce 

 phaltw is that of a perfect fish. Mr. Yarrell describes the vertebra 

 as having no spinous processes. It lives among sea-weed. 



(Montagu, in 2nd vol. of the Wemerian Memoirs ; Yarrell, British 

 Pishes, vol. ii.) 



LEPTOCLINUM. [BOTBYLLIDJS.] 



LEPTOCONCHUS (teirrb,, thin, and K<ty X os, a shell), Ruppell'i 

 name for a genus of Pectinibranchiate Gasteropodous Mollasca. The 

 genus is thus characterised : Head of tae animal with an elongatec 

 proboscis, but which is entirely retractile ; mouth without any apparen 

 armour; tentacles two, flattened, triangular, short, united at theii 

 Internal base, supporting the eyes at one-half of their length on their 

 external side. Foot moderate, muscular, without any operculum 

 Mantle with a circular border, without ornament, and with a slight pro 

 longation on the left side. Branchial cavity with a rather large aper 

 ture, the gill composed of a single comb formed of triangular lamina: 

 close get one against the other : at the bottom of this cavity is found 

 the orifice of the ovaria. whence (in the month of July) the eggs come 

 forth in numerous bundles (par paquets nombreux), each enveloped 

 in a viscous sac, which is flattened, elliptical, and three lines in length. 

 In the middle of the branchial cavity is the orifice of the anus. On 

 the right side of the neck, a little behind the right tentacle, there is 

 another orifice, which may have some relation to the male organs of 

 generation. 



Shell subglobular, delicate, fragile, translucent, with a low spire, 

 which U nearly effaced by the encroachment (surcroissement) of the 

 lamina; of the last whorl. Aperture large, suboval, with its two 

 extremities turned contrariwise, so that the aperture has some 

 resemblance to the letter S reversed ; the two margins not united, 

 the right one delicate at all ages, and a little expanded anteriorly as 

 in adult Janthina. No columella. No umbilicus. 



L. itriattu, Riippell. The shell of this species, which served Ruppell 

 for the type of the genus, is a rather dirty milk white ; it is furrowed 

 externally with numerous longitudinal undulated lines very much 

 approximated. Length of adult, 14} lines; breadth, 12J : young, 

 74 ; breadth, 6. 



Shell of Ltptoconchtu itnatus. 1, anterior view; 2, view of the back. 



It inhabits the Red Sea, where it is found imbedded in the calca- 

 reous mass of Polyparia, and having no communication with the water 

 except by a moderate opening. These corals prove almost always to 

 to be a species of Meandrina(if. Phrygia) in which Magilut, Venerupis, 

 4c., occur. 



Ruppell is of opinion, from the few words of M. Rang concerning 

 the young of Mayiliu, that the last-named naturalist had before him 

 the genus above described. Ruppell notices the following distinctions 

 between Lrptoconchus and Magilut. In the former the margins of the 

 shell are always disunited ; in the latter they are always united. The 

 animals of the two genera are distinguished by the possession of an 

 operculum in the one (Magilus) and its absence in the other, and by 

 the difference in the proboscis ; nor is the siphon of the Mayttus 

 present in Leptoconchus. 



Ruppell suggest* that Leptoconchus approximates to the Janthince. 

 The number of the tentacles, the oval proboscis, the mantle deprived 

 of a siphon, the pectinated branchiie framed of crowded pyramids, 

 and the absence of an operculum, favour thin approximation, as well 

 as the analogies of the shell ; but he adds that he is perfectly aware 

 that the difference of the habitations of the two genera is too great to 

 allow of a reliance on this suggestion. (' Transactions of the Zoolo- 

 gical Society of London,' vol. i. ; ' Proceedings ' of the same Society, 

 1834.) 



LEPTO'LEPIS, a genus of Fossil Ganoid Fishes, occurring in the 

 Liassic strata. 



LEPTOM/ERA. [L^MADIPODA.! 



LEPTOMERIA. [SASTALACEJ;.| 



LEPTON, a genus of Acephalous Lamellibranchiate Molluica, 

 belonging to the family Kettiada. This genus is closely allied to 

 KMia. Only three species have been described, two of which, 

 L. iqvamoium and L. convexum, are British. L. fabagella has been 



taken on the shores of the United States. The species are all smiill 

 and rare. 



LEPTOPHI'NA, the name given by Professor Bell to a sub-family 

 of Serpents belonging to the family Colubrida;. It is thus defined : 

 Head elongate, broad behind, narrowed before ; the anterior part 

 covered with nine scuta;. Eyes large. Gape wide, somewhat waved. 

 Maxillary and palatine teeth ; no poisonous fangs. Body very slender, 

 slightly depressed. Tail very long, slender, the point acute. Dorsal 

 scales oval, elongate, loose ; caudal scales very small, closely arranged. 

 Abdominal scuta very long ; subcaudal scuta small, indistinct. 



The genera Dryinus and Leptophis are included in this family, of 

 which Dryinua auratm and Leptophit purpwascew may be regarded 

 as examples. 



Dryinm auratia. Bell. 



" The whole of the serpents composing these genera live," sayt> 

 Jr. Bell, " in woods, entwining themselves amongst the branches of 

 ss, and gliding with great rapidity and elegance from one to 

 inother. These habits, combined with the graceful slenderness of 

 heir form, the beautiful metallic reflection from the surface in some 

 pecies, and the bright and changeable hues in others, place them 

 mongst the most interesting of the serpent tribe. Their food con- 

 ists of large insects, young birds, &c., which the extraordinary size 

 f the head, the width of the gape, and the great dilatability of tho 

 neck and body, enable them to swallow, notwithstanding the small 

 ize of these parts in a state of rest. In a specimen in my possession 

 f Dryinus auratus, for instance, the length of which is 4 feet 9 inches, 

 he diameter of the neck is hardly 2 lines. When the skin is distended 

 ither by food or during inspiration, the scales are separated from 

 ach other, and the skin, which is of a different colour, becomes 

 isible in the interstices, producing a curious reticulated appearance. 

 Notwithstanding the poisonous mark was affixed by Linnrcus to the 

 nly species of Dryinus known to him (Colubei- mycterizans, Linn.), 

 t is well ascertained that they are all of them perfectly harmless ; 

 nd it is asserted of that species that the children are in the habit of 

 aming and playing with them, twining them round their necks and 

 rms, and that the snakes appear pleased at being thus caressed." 



Di-yinus (Merrem). Upper jaw much longer than the lowor. 

 lostrum very narrow, more or lees acute at the apex, which in sonic 

 peoiea is distinctly mucronate and moveable. (Bell.) 



Mr. Bell records six species, three of which are American, Carolina} 



