HARDWICKE'S SCIENCE-GOSSIP. 



175 



and lateral openings. I cannot satisfy myself, how- 

 ever, of the existence of either of these in the 

 present instance. 



The chambers, which are seven in number in the 

 abdominal segments, seem, on the contrary, to be 

 separated only by slight constrictions of the wall of 

 the vessel, which is closely connected, on its upper 

 surface, with the integument, and on its lower with 

 a flat membranous expansion which flanks it on 

 either side, and is there prolonged into a series of 

 triangular points. These are affixed between the 

 muscles of the lateral bands, and are called by 

 Burmeister "wings of the heart": they number 

 about two pairs to every chamber, and present indi- 

 cation of a muscular character, in the striated 

 fibrilloe which traverse them. Their office appears 

 to be to dilate the dorsal vessel by pulling the lower 

 portion of its wall from the upper, as will be 

 understood by the sectional drawing I have given, 

 the subsequent constriction being effected by the 

 elasticity and slightly muscular character of the 

 walls themselves. 



The dilatation takes place not simultaneouslyalong 

 the whole length of the vessel, but progressively, 

 the wings in the vicinity of the anus being the first 

 to contract and dilate their portion ; and afterwards 

 those nearer the head in succession. Thus a wave 

 of dilatation is constantly passing along the vessel 

 in a forward direction, from the tail to the head of 

 the larva, sufficient, I think, to account for the 

 forward motion of its contents, without the pre- 

 sence of valves between the chambers, which, as I 

 have before said, I cannot detect. 



The dorsal vessel is destitute of wings or cham- 

 bers in the three anterior or thoracic segments, 

 which it traverses as a membranous tube, and 

 passing through the oesophageal nervous ring, 

 immediately above the oesophagus, it terminates by 

 a funnel-shaped opening in front of the brain, be- 

 tween the two muscles previously described. I am 

 somewhat inclined to think that in the membranous 

 expansions of the wings of the heart we have only 

 another form of the myolemma surrounding the 

 muscular fibres of the body ; that they are, in fact, 

 true muscles, each inclosed in a separate cellular 

 envelope, or myolemma, the muscular fibrillar being 

 very sparsely developed. A great number of oval 

 cells filled with granular contents, beset the bases of 

 the wings close to the dorsal vessel, and frequently 

 impede exact observations on iis structure. 



{To be continued.) 



A pair of live Sea-lions {Otaria ursina), male and 

 female, have just been added to the collection of 

 animals in the Jardin d'Acclimatation, Paris. They 

 have been brought from the North Pacific, and now 

 live in a large taok specially prepared for them. 

 They are said to be in excellent health. 



THE CEYLON JACKAL. 



{Canis aureus) 



A MONG the carnivora of Ceylon, of which there 

 J - 1 - are at preseut about twenty species identified, 

 the most numerous, and best known by its cunning 

 and adroitness, is the jackal (Cniis aureus). With 

 the exception of the very hilly country, it is to be 

 met with in all parts of the island, hunting in packs 

 and headed by a leader. From my own observation 

 and experience of the habits and retreats of these 

 animals, I certainly think that they partition the 

 jungles which they inhabit into districts, each 

 apportioned to a separate pack, by whom it is 

 jealously guarded from tho encroachments of all 

 intruders. During the day they are comparatively 

 inactive, keeping on the confines of the wood, in 

 the depths of which they find concealment and 

 shade, and from which they emerge only at twilight, 

 to go their usual rounds in search of prey, at which 

 time they utter the unearthly cry peculiar to their 

 race, which mostly resembles the sounds oikkay- 

 okky-oikkyl very loudly and rapidly repeated. 

 There is a mournful silence in the calmness of the 

 evening, when the tropical sun sinks upon the 

 horizon— a conviction that man has left the region 

 undisturbed to its wild tenants. No hum of dis- 

 tant voices ; no rumbling of busy wheels meets the 

 ear ; and in the wilderness, pathless and untrodden 

 by the foot of civilization, where no sound is ever 

 heard but that of the elements, when the thunder 

 rolls among the towering forest, or the wind howls 

 along the plains, one is suddenly startled by the 

 harsh cry of the jackal, made doubly loud by the 

 surrounding silence, which sounds very remarkable 

 in the stillness and solitude of the'night, and is well 

 calculated to awaken peculiar emotions. Sometimes 

 they wend their way towards the rivers and tanks, 

 and wait in ambush for the different species of deer, 

 which are compelled to resort thither to quench 

 their thirst; when they are very soon assaulted 

 aud torn to pieces by these audacious prowlers. 

 In the more northerly portions of the island, which 

 mostly consist of wide plains, thinly covered with 

 brushwood, diversified at intervals by little patches 

 of jungle, jackals are to be found in regular 

 swarms. The great scarcity of hares in this district, 

 elsewhere abundant, is ascribed to their depredations. 



In their hunting expeditions they especially dis- 

 play, in a high degree, their superior faculties of 

 instinct aud cunniug. Towards nightfall, having 

 marked the retreat of some small animal to its 

 sleeping quarters, they all surround it, taking the 

 precaution, however, to station a few to watch iu 

 ambush on the track by which the unconscious prey 

 entered. The attack is generally commenced by 

 the leader, for on raising his horrible cry, as the 

 word of command, the whole pack then rush into the 



