HARDIVICKE'S SCIENCE-GOSSIP. 



267 



evil of the two. M. Pasteur's scheme of infecting 

 the rabbits with the itch or scab, has been tried and 

 failed. 



For the information of persons who are not fully 

 aware of the prolific nature of rabbits, it may be 

 stated that in three years, under favourable circum- 

 stances, two pairs of rabbits, if undisturbed in any 

 way, and sufficient food abounded, would increase to 

 the enormous number of "'5,000,000 ; which fully 

 shows the necessity that exists for continuous and 

 vigorous action to destroy them. The extent of the 

 evil may be imagined from the fact that 15,000,000 

 rabbit skins have been exported from New South 

 Wales in one year, and that in the thirteen years end- 

 ing with 1SS9, 39,000,000 rabbit skins were exported 

 from Victoria, to say nothing of the other Australian 

 colonies. Twenty years ago there was not a single 

 rabbit throughout the length and breadth of Xew 

 Zealand. Since then more than 106,000,000 rabbit 

 skins have been exported from those islands. The 

 property destroyed by the rabbits is estimated by 

 millions. On the average, 12,000,000 skins are ex- 

 ported from New Zealand yearly. They increase so 

 rapidly, and the destruction wrought by them is of 

 such a character, that in some districts it has become 

 a question whether the colonists with their flocks and 

 herds should vacate the country, or whether sys- 

 tematic efforts should be made to extirpate the pest. 



In some Australian colonies the bounty offered 

 ranges from id. to is., according to the number in 

 the district. In Victoria there are a hundred official 

 inspectors and some 10,000 persons employed in 

 killing them. Any person having a live rabbit in 

 his possession is liable to a penalty up to loo/, on 

 conviction. 



In view of these animal scourges and pests which 

 prevail in other countries, we may be content to 

 bear patiently with our variable climate, where we 

 possess many comforts, and with good food and 

 salubrious dwellings enjoy an increasing degree of 

 longevity. 



POXD LIFE STUDIES. 



'So. III. — Cypris tristriata. 



Ey H. Durrant. 



AS with Cyclops and Daphnia, the little animal 

 whose name heads this short paper is quite 

 common, and belongs to the same order, viz., Bran- 

 chiopoda. General: The shell of Cypris is composed 

 of two pieces united along the dorsal margin by a 

 hinge, and bears a great resemblance to a bivalve 

 shell. Feet : Two pairs. First pair stronger than 

 the second, directed forwards, hooked, four-jointed. 

 Second pair situated on the middle of the ventral 

 surface, directed backwards, curved, hooked. Their 

 use is mainly in supporting the ovaries, and are very 

 rarely seen beyond the valves. Superior Entennce 



not so long as body, setaceous, composed of seven 

 or eight joints, the last are shortest, terminated with 

 from twelve to sixteen fine hairs, which serve the 

 insect in locomotion. Inferior antennae leg-like, 

 with a tuft of feathery filaments, five-jointed, last 

 joint with several curved hooks. Mouth parts com- 

 posed of a labrum, which is carinated, shaped like a 

 hood, and projects between the inferior antenna;. A 

 labium slightly elongated and triangular. Two 

 mandibles, toothed, furnished with a three-jointed 

 feeler. On the first joint of this latter organ, a 

 branchial lamina, five parted, occurs (interior lip of 

 Ramdohr). First pair of jaws consist of a basal plate, 

 with four movable finger-like silky appendages at 

 their extremity ; from the exterior edge there arises a 

 large branchial lamina, pectinated with nineteen 

 spines. Second pair of jaws, two-jointed, flattened, 

 terminal one furnished with a few rigid hairs and a 

 lateral palp-like process. Abdomen consisting of 

 two long portions, with a couple of terminal hooks 

 and a third at the upper edge. 



Specific : Cypris tristriata, Miiller. Carapace 

 oval, slightly reniform, green, covered with short 

 hairs. The ovaries form two large vessels on the 

 posterior side of the body and opening at the anterior 

 portion of the body. The canal formed by the 

 tail establishes a communication with them. They 

 are conical and simple. Eggs spherical. No dis- 

 tinct joint in the body, which at its posterior termina- 

 tion is formed into a sort of tail with a couple of 

 setaceous filaments fringed at the end with three 

 minute hairs. The lower lip is composed of a sort 

 of compressed sternum (external lip of Ramdohr). 



Life-history. — When the time of egg deposition 

 arrives, the female lays them in a mass on the water- 

 plants or very often on the bottom of the pond or 

 ditch, and in doing so uses a glutinous substance, by 

 means of which they are firmly fixed to their support. 

 The occupation of egg-laying is one which takes 

 considerable time in this little species, two or three 

 hours being required for the deposition of about 

 twenty eggs, and all this time she is anchored by tier 

 second pair of feet to -guard against being'swept away 

 bodily by the force of the water. In swimming, the 

 members of this genus use the filaments of the 

 antennae, sometimes only using one, at other times 

 the whole lot. The first pair of feet also assist the 

 animal greatly, although when they come to be used 

 for journeying over water-plants, etc., it seems they 

 are of very little use, and progress is slow. Besides 

 being used as organs of locomotion, the filaments of 

 the antennae are thought by Latreille to be used as 

 organs of respiration, a very probable theory. 



Here are some notes I made last year on the 

 moulting of this species : — 



April loth. — A female deposited eggs to the num- 

 ber of twenty-one. The time occupied was exactly 

 one hour and three quarters. Immediately after 

 deposition she changed her skin. 



