DIRC A DISCOBOLUS. 



291 



of the resinous juice which it furnishes. Its properties 

 may be said to be stimulant and balsamic. 



The chief genera of the order are, Dipierocarpus, 

 Dryobalanops, Shorea, and Valeria. 



Dryobqlanops Cuniphora is interesting on account 

 of yielding the camphor of Sumatra. In that island 

 this tree is confined to the country of the Battas, 

 which extends about one degree and a half to the 

 north of the equator, It is also found in Borneo in 

 nearly the same parallel of latitude. The camphor 

 is found in a concrete crystallised state in fissures 

 and cavities in the interior of the tree. It is less 

 volatile than the common camphor of commerce, 

 which is the product of Laurus Camphora, a native of 

 Japan and China. On account of its scarcity it bears 

 a very high price. It is little known in this country, 

 or even in Europe. An oil is procured from the 

 camphor tree by incision, which is supposed to be the 

 first stage of the formation of camphor. 



An account of camphor and its medical uses will 

 be given under the article LAXJRINEJE. 



Shorea robusta affords a balsamic resin, which is 

 used in the Indian temples. 



By boiling the fruit of Vateria Indica, a tree com- 

 mon on the Malabar coast, a kind of tallow rises to 

 the surface which concretes on cooling. It is whitish, 

 greasy to the touch, and has rather a disagreeable 

 odour. It is extremely tenacious and solid, but melts 

 at the temperature of 97^ Fahrenheit. In the town 

 of Mang-alore it is sold for about twopence halfpenny 

 a pound. 



DIKCA (Linnaeus). A small deciduous shrub, 

 native of Virginia, in which country it is called leather- 

 wood, perhaps from the toughness of the fibres of the 

 inner bark. The flowers are inconspicuous, are octan- 

 drious, and the plant belongs to the natural order 

 ThymdaECE. It is usually planted among North Ame- 

 rican plants, and is propagated by layers. 



DISA (Bergier). A genus of curious flowering 

 plants, natives of the Cape of Good Hope. Linnsean 

 class and order Gynandria Monogynia, and natural 

 order Orc/iidece. These plants thrive best planted in 

 a pit with other Cape bulbs or tubers, in soil com- 

 posed of loam, moor earth, and sand. They only 

 need water when in a growing state. 



DISCINA (Lamarck). This genus of molluscs 

 has been so called from each valve presenting, near 

 the centre, a remarkable and very distinct orbicular 

 disk ; that on the superior or upper side is smooth and 

 pierced, exhibiting in its centre a small papillary ele- 

 vated summit, giving it much the appearance of a 

 patella : it is also surrounded by a margin longitudin- 

 ally marked with delicately radiating striae. The disk 

 of the lower margin is very white, obliquely crossed 

 by a notch or cleft, open on both sides. Although the 

 valves of the shell are of an equal size, they are not 

 exactly similar, the upper one being rather more con- 

 vex, and the lower without striae round its disk : there 

 are no traces of hinge, ligament, or muscular impres- 

 sions visible. It is found on the British coast affixed 

 to stones. Sowerby observes this genus should be 

 entirely expunged. Lamarck having constituted it 

 from examples of the Orbicula, without mature con- 

 sideration, it therefore must now form a subdivision of 

 the genus Orbiculina. 



DISCOBOLUS, so called from the ventral fins, 

 forming a disk on the under part of the body, by 

 means of which the fishes are enabled to hold on upon 

 the points of rocks, and there catch their food, which 



is brought to them by the currents. They form the 

 third family of Cuvier's soft finned fishes, with the 

 ventrals under the pectorals. They are fishes of 

 small size, and altogether uninteresting for econo- 

 mical purposes. They are, however, curious on 

 account of their form, and of the habit which we have 

 mentioned. There are only two genera in the family, 

 and the species are not numerous. 



LEPADOGASTEII the Sucker. The members of 

 this genus are very small fishes ; their pectoral fins 

 are very large, and reach the middle of the under 

 part. They are composed of very strong rays, a little 

 divergent in the front, and united by a membrane 

 which is elastic, and which also includes the ventrals. 

 Their bodies are smooth and without scales, the head 

 depressed, and the muzzle projecting and capable of 

 distension. Their gill openings are small, with four 

 or five rays in the gill-flap. They have one soft dor- 

 sal fin immediately over the anal. Their intestinal 

 canal is short, straight, and without those appendages, 

 which would show that they are animal feeders. They 

 have no air bladder, notwithstanding which they 

 swim with considerable rapidity. There are several 

 species found in the European seas, and on the British 

 shores ; but on the south and west rather than the 

 east. The following are the British species. 



L. CORNUBIENSIS the Cornish Sucker, is about 

 four inches in length, and reddish, with dusky spots. 

 When full grown there are two eye-shaped marks 

 behind the eyes, with a brownish marginal ring, a 

 bright purple disk, and a small spot of intense blue in 

 the centre. There are also four little fleshy filaments 

 in front of the eyes, and the snout is produced, rounded 

 and flattened. They are met with on the coast of 

 Cornwall, and also in some parts of the Hebrides ; 

 and there is no doubt that if they were of any value 

 to the fishermen they might be found upon all the 

 rocky shores which are washed by the Atlantic, espe- 

 cially where a current of tide sweeps along. They 

 are met with at low water adhering to the rocks, by 

 means of their disk. 



L. BIMACULATUS Two-spotted Sucker. The 

 length of this species is only about an inch and a half, 

 and the body is more slender and the snout more 

 pointed than in the former, and it is furnished with no 

 appendages in connection with the eyes ; the general 

 colour is pink spotted with white ; and when mature 

 there is a spot of purple with a white margin behind 

 each pectoral fin. This species is found in the Channel, 

 and does not app.ear to be so decidedly a current fish 

 as the other ; but it adheres to stones and shells. 

 These two species have the dorsal and anal fins dis- 

 tinct from the caudal ; but there are several species 

 which inhabit the Mediterranean which have these 

 appendages united. There is nothing, however, in 

 their history which can particularly interest the general 

 reader. 



CYCLOPTERUS Circular Fin. The most remark- 

 able structural character of this genus is that from 

 which it is named. The ventral fins are united into 

 one disk, which surrounds a considerable portion of 

 the under side, forming a very efficient sucker, by 

 which they can fix themselves firmly to rocks, to the 

 bottoms of ships, or to the bodies of the larger fishes. 

 Their mouths are large, and furnished with small 

 pointed teeth in both jaws, and also in the pharynx. 

 Their gill openings are small and closed below, with 

 six rays in the flap. Their pectoral fins are very large, 

 and they are continued and united under the throat, 

 T2 



