April 1, 1S69.] 



HARDWICKE'S SCIENCE-GOSSIP. 



75 



external surface of tins ocean cradle abounds in 

 tubercles which, as well as other parts of its walls, 

 are perforated with rounded and puckered orifices 

 through which currents of water are observed to 

 pass : an external membrane and an internal lining 

 containing between them a pulpy substance, are 

 distinctly visible : the length of this case is precisely 

 five-eighths of an inch, and its breadth half an inch. 

 The ova and the young are secured by a filmy band 

 running round the interior about half way up it, 

 they are indistinctly visible through the case as 

 shown in the illustration. 



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Fig. 50. Phronima sedentaria, x 2. 

 Drawn from life by Dr. J. D. McDonald, R.N., F.R.S., F.L.S. 



The mother when swimming, has her head and 

 the three first segments of the thorax inserted into 

 the tube which she holds fast by means of the third 

 pair of legs — which have been mentioned as being 

 habitually thrown forwards across the head — which 

 have their claws .firmly driven into the lining 

 membrane of the case, in front of her head. The 

 formidable " pinchers " of the fifth pair remaining 

 outside " clear for action " in readiness to meet an 

 enemy, and the swimmerets on ordinary occasions 

 are busily paddling as repi-esented in the drawing. 

 Sometimes on the approach of danger she draws the 

 whole of her body within the tube, and apparently 

 to guard against the risk of being shaken out by the 

 shock of a collision, drives the claws of the seventh 

 pair of thoracic feet (which seem to be normally 

 directed backwards for the purpose) into the lining: 

 the anterior (third) pair being, as we have seen, 

 similarly directed forwards ; she has thus a firm 

 " set " against a jerk coming either way. Her great 

 compound eyes placed not only in the sides, but in 



the top and back of her head, enable her to take in 

 with one marvellously comprehensive glance the 

 whole circle of her brood; the objects of her 

 maternal solicitude, they are never " from under her 

 eye ;" no human beings are under such complete and 

 constant supervision as the fry of Phronima. 



The specimen from which our '- illustration was 

 drawn, was kept alive for ten days. She was a 

 creature of the liveliest habits, whirling about in 

 rapid gyrations, and turning summersaults, tub 

 foremost, with a very comical effect. She never 

 progressed in right lines, but first ascended at an 

 angle of about 75° with her ventral aspect towards 

 the spectator, then suddenly twisting sharply 

 towards the left, she threw her tail up, and came 

 down head foremost at a like angle, bringing her 

 right side and the back of her head into view. 

 Sometimes she was seized with a mania for waltzing, 

 spinning round and round without materially 

 shifting her ground, like a buoy moored in a strong 

 tideway : merry little Phronima was often placed on 

 the wardroom mess-table by particular request, her 

 strange antics affording much amusement : but she 

 pined for the liberty of the free ocean, and drooped, 

 and died " universally respected and regretted." 



It does indeed seem strange that the preservation 

 of the species, the safety of the broods of this tiny 

 inhabitant of the deep, should hang upon the 

 apparently doubtful contingency of the mother 

 picking up just at the critical moment a suitable 

 piece of the broken skeleton of another and widely 

 different creature : but the plans of the great Master- 

 builder however inscrutable to us, never fail ; and 

 we see, if we study the glorious pages of nature's 

 outspread book intelligently and reverently, that, the 

 ends aimed at are ever infallibly attained. " We 

 see on every side of us innumerable adaptations and 

 contrivances, which have justly excited in the mind 

 of every observer the highest admiration. There is 

 for instance a fly (Cecidomyia) which deposits its 

 eggs within the stamens of a Scrophularia, and 

 secretes a poison which produces a gall on which 

 the larva feeds ; but there is another insect 

 (Misocampus) which deposits its eggs withm the 

 body of the larva within the gall, and is thus 

 nourished by its living prey ; so that here a 

 Hymenopterous insect depends on a Dipterous 

 insect, and this depends on its power of producing a 

 monstrous growth in a particular organ of a 

 particular plant. So it is in a more or less plainly 

 marked manner in thousands and tens of thousands 

 of cases, with the lowest as well as with the highest 

 productions of Nature." With this quotation from 

 Darwin, let us wind up our gossip about this little- 

 known and seldom seen Amphipodous Crustacean, 

 trusting that time and the towing net may yet 

 enable us to obtain fuller and more perfect details 

 for the information of our readers. 



Bury Cross, Gosport. 



