HARDWICKE'S SCIENCE-GOSSIP. 



267 



at other times have seen three on both sides always. 

 Lord Osborne, who specially studied the teetli of 

 rotifers, observed the same variation in Philodma 

 roseola, and other observers in other species. It may 

 be a case of knowledge coming and wisdom lingering, 

 the third tooth being only cut late in life when versed 

 in the ways of the world. 



Two eyes may sometimes be seen in Rotifer tardus, 

 in the neck, just above the mastax, which possibly 

 might cause confusion ; these belong to a fcetal animal ; 

 but one has to look so far down before one comes to 

 the second mastax, that it might be taken for a 

 Philodine. It is worth observing if the foetal posi- 

 tion is always the same, if so, it might be a means 

 of easily separating closely allied species. The head 

 is upwards in Rotifer vulgaris and tardus, downwards 



L 



'n^-'y./:/, 



Fig. 154. — Distyla Fig. 155. — Distyla flcxilis (side view.) 

 flexilis (front view). 



in Philodina aculeata, Philodina tuberculata, and Roti- 

 fer macrurus, but is this invariable ? 



The colour of this rotifer varies considerably, 

 probably chameleon-like from the tint of the flocculent 

 deposit in which it lives ; some may be found quite a 

 light yellowish-brown : these are the younger ones, in 

 these the internal organs are more easily seen ; the 

 mastax is surrounded by a considerable glandular 

 mass, the buccal funnel stands out like a pouch from 

 the front of the animal, its margin fringed with cilia, 

 and leads straight down to the mastax, immediately 

 under which is a large oblong stomach separated by 

 a constriction from a similar shaped but smaller 

 intestine, on the other side an oval ovary fills up the 

 body. 



The antenna (Fig. 153), is long, two-jointed, the joint 

 very faintly marked ; at the end are three small lobes 

 fringed with cilia. The frontal column (Fig. 152), 

 is rather wide in proportion to its length ; among the 

 cilia a small cleft proboscis may be seen immediately 

 before the wheels expand. The tubercules are not 



well marked, and appear to be formed by the folds 

 of the trunk ; in its fully extended state, when it 

 becomes worm-like, resembling Rotifer vulgaris, the 

 tubercules almost disappear. 



Philodina aculeata, frequently found with the one 

 under consideration, is of a yellow hue, has the 

 distinctive spines, the wheels do not exceed the 

 width of the body, the spurs are small, and the end 

 joint of the antenna is wedge-shaped, base forward. 



No. 5. — Distyla Flexilis. 



This rotifer, belonging to the family Cathypnadse, 

 which includes the common Cathypna luna, is repre- 

 sented in front view. Fig. 154, and in side view. Fig. 

 155. Mr. Gosse places it in the genus Distyla with 

 some hesitation ; there is indeed but little distinction 

 between Distyla and Cathypna, the former being 

 longer in proportion to width ; and the curious lateral, 

 bellows-like, infolding characteristic of the family 

 being less marked. 



In this group may be observed something like a 

 state of sleep ; the animal perches on its claw-like toes, 

 bent at an angle under its body, and remains motion- 

 less for a time, as if visited by that "gentle sleep 

 beloved from pole to pole," which most rotifers seem 

 not to require. The little rotifer has to exercise 

 greater perseverance than the little ant to acquire its 

 daily provender, and, examine it when you may, from 

 morn to dewy eve, or in' the silent watches of the 

 night, it is ever in a state of ceaseless activity. This 

 group is interesting from being an exception to this 

 general rule. 



Distyla flexilis is small, about f|g inch long and 

 without colour, except the one rose-red oblong eye, 

 and a yellowish tinge in the stomach. The body is 

 covered with folds, giving it an irregular tesselated 

 appearance and making the outline fuzzy under a low 

 power. It is active in its attacks on food, but 

 remains near one spot for a long time, occasionally 

 swimming about to seek "fresh fields and pastures 

 new," yet I have left it under a \ objective, and at 

 the end of an hour have found it still in the field. 



This rotifer separates its toes laterally like pincers, 

 and seizes objects between them as if to get a better 

 hold. The one figured came from Wimbledon 

 Common, and was abundant in some water given me 

 by G. Western, Esq. 



A DAY AMONG THE TERTIARY DEPOSITS 

 OF MALTA. 



By John H, Cooke, B.C., F.R.G.S. 



ACCOMPANIED by a boy, whom I had engaged 

 for the purpose of carrying my geological 

 paraphernalia, consisting of a well stocked provision- 

 bag and my two favourite hammers, I left Valletta 

 just as the dawn of a cloudy September day was 

 asserting itself in the east. In England, a necessary 



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