749 



SKNSOEIUM. 



SEPIAD-E. 



7M 



The movements are not alone produced by mechanical irritants, for 

 if various corrosive substances, aa bichloride of mercury, sulphuric 

 acid, caustic potash, &c., are applied to the knots of the joints, the 

 same phenomena are observed. The removal of the plant to a higher 

 temperature will produce the same result, as well as exposing it to a 

 lower temperature or a draught of cold air. They are destroyed by 

 the application of chloroform and other anesthetic agents. 



Besides the Mimosa pudica there are several other species belonging 

 to this genus that possess the same property, though not in so remark- 

 able a degree. Amongst them may be named if. sensith-a, if. viva, 

 M. casta, M. aj>erata, M. quadrivalvis, M. pernambucana, M. pigra, 

 M. humilii, M. peltata, it. dormiens. Species of other genera of the 

 tame natural order Leyuminosce exhibiting these movements are 

 Smithia teraitiva, jEschynomene Indica, jE. pumila, and Desmantkus 

 siolonifer. The locust-tree when its branches are roughly shaken 

 closes up its leaves, and the same has been observed of Gledttschia 

 Iriacantha ,and it is probable that close observation during hot weather 

 would prove that other leguminous plants possess this property. 



Another family of plants that exhibit sensation when touched or 

 stimulated is Oj-alidaceas. The 0:calis senfitiva, called by De Candolle 

 on account of its sensitive properties Biophytv/m,, has long been known 

 to possess this property. Averrhoa bilimbi and A. carambola are both 

 plants belonging to Oxalidacetc, and have been described by travellers 

 as possessing the property of folding their leaves on the application 

 of a stimulus. But it is not only in these species that this property 

 resides, for Professor Morren of Liege lias observed it to occur more 

 or less ) u all the species of the genus Osalit. His observations were 

 first made on the Oxalii ttricta, which, if hit smartly on a warm day, 

 will contract its leaves and assume a position as in the ordinary sleep 

 of the leaves of these plants. He has also observed the same move- 

 ments in 0. Acct"-tMa and 0. corniculata, and many extra-European 

 species. The movements in these plants consist in the folding up of 

 their leaves, so that the two halves of the leaf approach each other by 

 their superior surface. The midrib is also slightly bent, so that its 

 inferior surface presents a convexity ; and the petioles of the leaflets 

 bend downwards, so that the leaf, when irritated, becomes dependent. 

 (Morren, ' Notes sur I'Excitabilite' et le Mouvcment des Feuilles chez 

 les Oxalis,' in the 6th volume of the ' Bulletins de I 1 Academic Royale 

 de Bruxelles.') 



In the family Droteracece, or Sun-Dews, are some plants which 

 exhibit a considerable amount of irritability. The leaves of Dioncea 

 miucipula, or Venus's Fly-Trap [DION^EA], have the remarkable 

 property of contracting upon insects that may happen to alight upon 

 their surface. None of the Sun-Dews inclose insects in their leaves in 

 this manner, but the surface of their leaves is covered with long hairs, 

 which secrete a viscous matter. When any insect settles upon the 

 leaf, it is entangled with the viscous secretion ; and before it has time 

 to escape, the hairs exhibit a considerable degree of irritability, and 

 curving round, pin the animal down on the surface of the leaf. 



Other instances of vegetable irritability occur in the Berberii 

 vulyarii, Mimulva, and Stylidium. [BEiiBERls; MlMdLUS; STYLIDIUM; 

 MOTIONS OF PLANTS ; CYCLOSIS ; SAP.] 



SENSORIUM. [NERVOUS SYSTEM.] 



SEPAL. [CALYX.] 



SE'PIA. [SEPiAD-e.] 



SE'PIAD.<E (2))io), a family of Cephalopodous Molluaca, including 

 the forms which are ordinarily known under the name of Cuttle-Fishes. 



The genera comprehended under that term have been thus denned : 

 Animal in the form of a snc or purse, with or without fins ; head 

 large, very distinct, crowned with brachial appendages to the number 

 of eight or ten ; arms very unequal, always furnished with suckers on 

 their internal surface, with or without hooks ; branchiae pyramidal ; 

 orifice of the organs of generation opening into the branchial pouch, 

 which last communicates with the external surrounding medium by a 

 sort of funnel, the tube of which opens uuder the neck. Shell mono- 

 thalamous or rudimentary, sometimes horny or cellular, but never 

 polythalamous. (Rang.) 



Dr. Leach divided the group of Cuttles into two families, the 

 Octopods and the Decapods. The forms belonging to the first division 

 are described under the article OCTOPODA. 



The Decapoda are thus defined : Animal generally elongated, 

 cylindriform, having a thick sac, furnished with natatory expansions; 

 head very distinct, crowned with ten arms, eight of which are sessile, 

 shorter than in the Octopods, and furnished with acetabula or suckers 

 along the whole length of their internal surface, and two much longer 

 (tentacula), which are retractile, not situated on the same lino with 

 the arms, pediculated, and furnished with suckers, which are situated 

 ordinarily on the enlarged and terminal portion only.? No shell, 

 but only a testaceous rudiment or support, which is either carti- 

 laginous or calcareous in the interior of the back, in the greatest part 

 of the genera. 



Under this division are placed the Teu,t/iid<c, or Calamaries, and the 

 true Stpiadrf, or Cuttle-Fishes, properly so called. 



f-'rpiola {Kondeleliut, Leach). Head of equal breadth with the body, 

 owing to the magnitude of the eyes. Body scarcely ventrieose, sup- 

 ported by a-thin flexible transparent dorsal lamina, and with natatory 

 organs extended from the siHcs of the body. 



8. vvlga.ni, Grant; S. Atlantica, D'Orbigny. Dr. Grant, in a paper 



on this species, describes the body or mantle of the specimens 

 obtained on our coast as measuring generally about six lines in length, 

 and as much in breadth, whilst the head measures only four lines in 

 length, and, from the magnitude of the eyes, is equal in breadth with 

 the body. The arms are of unequal lengths, the longest being about 

 an inch long, and the shortest about a line less. The first or dorsal 

 pair are the shortest, the second and fourth equal in length, and a 

 little longer than the first pair ;' and the third pair the longest. This, 

 Dr. Grant observes, is the order of the comparative lengths of the 

 arms most common in the naked Cephalopoda. The third and fourth 

 arms on each side are connected to each other by a musculo-mem- 

 branous fold, which extends to about a third of their length, and is 

 covered by the skin and subjacent coloured parts. The late Professor 

 E. Forbes has observed that this species changes its colour according 

 as it is exposed to light. 



Rondeletii is a second British species, a single specimen of which 

 was taken in Ireland by the late Mr. W. Thompson, and another in 

 England by Mr. Joshv.a Alder. 



5. itenodactyla is a species from the Mauritius, described by Dr. Grant 

 in the ' Zoological Transactions." 



Three other species of Sepiola have been described. They are very 

 generally distributed. 



1,2, Sepiola stcnodactyla, back and front views (reduced) ; 3, Sepiola vulgaris, 

 back view (natural size). (Grant, ' Zool. Trans.') 



Rossia (Owen) has the body ventricose ; two wide rounded sub- 

 dorsal fins ; anterior margin of the mantle free. Arms rather short, 

 trihedral ; the acetabula pedunculated ; the peduncles very short, in 

 two alternating rows at the base of the arms, aggregated in many rows 

 at their point: order of the length of the equal arms, 1, 2, 4, 3. 

 Tentacula equalling the body in length, furnished at the apex with 

 many very small pedunculated acetabula. Gladius horny, 9 lines in 

 length, a little dilated below. 



It. palpebrota. Professor Owen, who established this genus upon a 

 Cephalopod brought from the Arctic regions by Captain James Ross, 

 R.N., and taken near the beach at Elwin Bay, Prince Regent's Inlet, 

 on the 29th of August 1832, states that it differs from Sepiola and 

 Sepioteuthit in the form, proportions, and position of its lateral fins, 

 and iu the extent of its horny dorsal style or gladius. In these 

 respects, he observes, it bears a closer affinity to Scjiiola, but differs 

 from it generally in having the anterior margin of the mantle free in 

 the whole of its circumference ; its natural position is therefore, in 

 his opinion, intermediate to Sepiola and Sepioteuthis, which it connects 

 together, as well by its intermediate size as by the peculiarities of its 

 structure. 



The details of the anatomy of this animal will be found in the 

 Appendix to Captain Sir John Ross's ' Second Voyage.' The ink-bag 

 was situated between the liver and the muscles which surround the 

 arms, close to which its duct entered the intestine. The ink was black, 

 of the same tint as the China ink. 



With reference to the remarkable development 'of the skin surround- 

 ing the eyeball (whence the trivial name palpebrota,), by means of 



