TEC 



141 



TEE 



Shell of Dolabella Rumphii. 1, inside ; 2, outside. 



Natural History of the Aplysians,' have, he remarks 



added many important observations on the animals of this, 



group. M. Rang, in his work, having especially studiec 



the Aplysians, has, as we have above seen, proposed to 



admit into this family three genera only, Aplysia, liiirnit- 



/'//./, and Arta>o//, and he divides the great genus Aplysia 



into sub^rnera, among which is found the genus Dolabella, 



Lam. There too is to be found the genus Noturchus, Cuv. 



This last, observes M. Deshayes, has in fact much analogy 



with the Aplysians, but it preserves some peculiar charac- 



ters capable of easy distinction ; and he thinks that the 



great ^enus Ajilyxiii, as considered by M. Rang, ousrbt to 



be adopted. Lamarck established his genus Drtlln ll, 



and separated it from Aplyaia because the shell is calca- 



reous, and not entirely corneous, as in that genus. La- 



marck, without doubt, continues M. Deshayes, would have 



perceived the little value of this character if he had been 



able to examine as many species as did M. Rang : he then 



would have seen the establishment by insensible gradations 



of a passage between Dolabella and Aplysia, not only 



with reference to the form of their shells, but with regard 



to their consistence also. With regard to the posterior 



truncation of the animal of Dolabellu, that may be seen 



to disappear insensibly, so that there exist Dolabella: with 



a calcareous shell, having entirely the external form of 



Ajilysiff. If, on the one hand, we see the Aflysiee with 



calcareous shells (Dolabellae) pass into those with corneous 



shells, we perceive on the other hand Aplysia with horny 



shells pass into species which have no trace of such pro- 



1 ret ing body. These remarkable species have the lobes 



of the mantle less slit, more closed upon the back, and 



nevertheless preserving Hie principal characters of the true 



l/'/i/xif/: M. Rang has established on these species his 



subgenus Ai-li'fia, remarkable for the singular tentaculi- 



form appendages on the bodies of the species which form 



it. Next to Ai>/yxiu M. Rang places .\'>t'ir<-hw>, and the 



trehi are .l/i/i/xuc which have only two tentacles, and 



whose mantle is more closed on the back than it is in the 



preceding genus ; the foot is extremely narrow, it is ter- 



minated anteriorly by a double lip, and resembles rather 



the foot of the K-yt/,rrr and other mollusks which creep 



on the stems of sea-weeds, than that, of the Aplysia;. It 



is to be wished, adds M. Deshayes, that the Notarchi 



could be found in sufficient numbers for dissection, by 



which means all doubt with regard to them would vanish. 



After the genus Aplysia, M. Rang places Bursatella ; 



and M. Deshayes remarks that this genus has so great an 



analogy with \ntarchun, that a new anatomy of the former 



is much to be desired. The animal seen by M. de Blain- 



ville was much contracted in the spirit, and its body was 



with a small number of tentacular appendages, 



which approximate it to the subgenus Aclesia, whilst in 



form it appears to come nearer to Nntnrcliux. The last 



genus, says M. Deshayes in conclusion, placed in the 



family of Aplysians bv M. Rang, is the Acteeon of Oken, 



which is not sufficiently known to be definitively admitted 



into the system ; so that the family of Aplysians may be 



rigorously reduced to the genus Aplysia, as considered by 



M. Rang. 



Notarchus. 



Notarchus Cuvieri. 



TE'CTONA, a genus of the natural family of Verbenacefe 

 so named by Linnaeus from the Indian name (Tehha) of the 

 famous Teak-tree (called also Sagoon}, which is a native 

 fferent parts of India, as well as of Burma, chiefly 

 s banks of the Irrawady, and of the islands from 

 Ceylon to the Moluccas. The genus is characterised by 

 wing a 5-6-toothed calyx, which becomes inflated 

 the growing pericarp. Corel 1-petalled, 5-6-cleft 

 lens 5, but often 6. Germ superior, 4-celled, cells' 

 .eeded, attachment central. Drupe obtusely 4-sided 

 "oo ly spongy, dry, hid in the calyx. Nut hard? 4-celled 

 Seed solitary. Embryo erect, without perisperm. 



6 * WS t( a " immense size ' and is 



mal furnished with a very small dorsal slit, which is 

 sometimes oblique; foot elongated, and rather narrow ; 

 bninchkB oi'ti-n very long, and capable of being protruded 



i i he cavity; opcTculum rudimentary or null. 

 HhoM null. * 



able fnr sze ' an s '-emar- 



for its very large leaves, which are from 12 to 24 

 nches long and from 8 to 16 broad, and are compared bv 

 Oriental wnters to the ears of the elephant. TheSles 

 s well a, the young branches and flower-stalks.are all 

 4-sided and the sides channelled. The inflorescence is in 

 'ery large terminal panicles, of which the divisions are 

 i rst cross-armed and finally dichotomous, with a sessile 

 tile flower in each cleft, the whole covered with a hairv 

 annaceous substance. The flowers are small, white and 

 ery numerous. As teak timber is so highly valued both for 

 omestic purposes and for ship-building, it is desirable to 

 otice its distribution a little more in detail. The best 

 mber for ship-building was supplied to Bombay from the 

 mountains of the Malabar Ghauts, where the tree is found 

 ather in detached clumps, of some extent however, than in 

 tended forests. It is also found on the mountainous 

 arts of the Coromandel Coast, along the banks of the 

 -rodavery up to Poloonsha. It proceeds far into the 

 itenor of India, and may be seen in the mountains of 

 undelcund, in the form however of only a moderate-sized 

 irub. Dr. Roxburgh introduced the teak into the low 

 grounds of the Circars as early as 1790, and Lord Corn- 

 wilhl and Colonel Kyd planted it in Bengal about the 

 same time. The Calcutta Botanic Garden contains a num- 

 ' o c ^ e trees- From the Saha runpore Botanic Garden 

 KN. lat. (where, its buds being covered with scales 

 t is enabled to resist 'cold, besides its leaves falling and 

 gi\ mif it a season of rest), the tree has been spread along 

 the Doab Canal ; the whole of the intermediate country 

 is suited to its cultivation, and the East India Company have 

 recently ordered the Malabar forests to be preserved. The 

 most extensive forests are however those extending along 

 the banks of the Irrawady, especially in Pegu. A con- 

 siderable timber-trade has been established at Moulmein, 

 whence Calcutta is supplied with some of the finest teak 

 timber. So much straight timber is taken and the crooked 

 left, that thousand of pieces called ' shin-logs,' and admir- 

 ably adapted for ship-timbers, are left. The tree grows 

 quickly, straight, and lofty, but requires from 00 to 80 

 years to attain the proper size and maturity for ship-build- 

 ing. 



From extensive experience teak timber has been found 

 the most valuable timber for ship-building, and has been 

 called the oak of the East. The wood is light, brownish- 

 coloured, easily worked, but at the same time strong and 

 durable. It is soon seasoned, and, from containing a resin- 

 ous oil, resists the action of water, as well as insects of all 

 kinds. It does not injure iron, and shrinks but little in 

 width. Some of the old trees have been found by Dr. 

 Horsfteld to have large and beautiful burrs like the Kia- 

 bouca wood of commerce. No other part of the tree is 

 known to be converted to much use ; but the leaves are said 

 to dye cotton and silk of a purplish colour. They have 

 lately been imported into the London docks carefully rolled 

 up, but for what purpose is not known. 

 TECTUS. (Conchology.) [TROCHIIXE.! 



TEES. [DURHAM.] 



