248 



HA RD WICKE'S SCIENCE- G OS SI P. 



I washed the house and gave the frog a cold water 

 bath, after which it became flat and had its usual ap- 

 pearance of health. On the 28th, I put two beetles 

 (Pterostichus madidus) into its house, both of which 

 ran very actively, and the frog leaped violently and 

 tampled on them till they were soon very quiet, but 

 it ate none of them ; another beetle was then put in, 

 but it was not eaten; during the night froggy left his 

 house, and was found the following afternoon. On 

 the 6th August, put in his house a large cockroach or 

 "clock " (Blalla orientalis), but it was not eaten ; the 

 frog afterwards ate a large daddy-long-legs, and 

 another on the morning of the 7th, and again two 

 on the 23rd, but it was some time before all their 

 long legs were wholly swallowed, and it again had 

 another on the 29th. On the 1st of September, I 

 housed a young toad along with the frog. The toad 

 {Buffo vulgaris) was only about three-fourths of an 

 inch in length, and for some time it lived along with 

 the frog, generally seated on its back, but it finally 

 disappeared, I believe swallowed by the frog. On 

 the 14th, gave three nearly full-grown larvae of 

 Hadena oleracea, which it swallowed, making great 

 use of its forefeet in defending [its eyes ; after this, 

 on the 1 6th, the frog was very uneasy, and its skin of 

 a blackish colour, but after a cold water bath, of 

 which it was very fond, it returned to its usual 

 yellowish colour. On the 18th, for some time it 

 watched a species of julus, but afterwards took a 

 snail in preference to it. On the 22nd, I gave the 

 frog a large earwig (Foricula auricularia) which 

 proved the cause of its death. 



From such an extractive summary of the frog in 

 domestication, I think certain conclusions may be 

 drawn. In selecting certain animals as food, and re- 

 jecting others, does not the frog learn from experience ? 

 In no instance do we find this specimen eating of the 

 centipede (Lithobius forcipatus), probably because it 

 had eaten of the same creature when in the fields and 

 had learned its mistake. In accordance with this we 

 find that at first it ate slaters or woodlice, but afterwards 

 left them alone. Taking beetles at one time and not 

 at another does not agree so well, but this may admit 

 of another explanation, viz. the state of the frog's 

 he; lth. See the iSth and 28th July, as above. It is 

 a well-known fact that frogs are fond of, and live a 

 good deal on, beetles. In the summer of 18S1, I 

 found several specimens of the ghost, or hissing 

 beetle (Cychrus rostratus), in the stomach of frogs 

 take:i on a broom-covered hill. On the 8th 

 July, when none of the beetles were eaten, there is 

 indication of the creature being more or less sick, as 

 it left. its house — a feat it seemed to perform only 

 when in want of water or in a sickly condition. 

 The frog left its house by creeping under the edge of 

 the beaker, and then leaped off the toj:> of the 

 drawers on which its house stood. It thus left its 

 house on the 8th, 19th, and 20th of August, and on 

 some other dates, when it often remained at large in 



the room for a day and a night, and as a rule was 

 generally found hidden in one of the children's 

 slippers or boots — a mark of the frog's natural habit 

 to hide in a hole or crevice. 



Taylor, 

 Sub-curator, Free Museum, Paisley, N.B. 



(To be continued.) 



CHATS ABOUT ROTIFERS. 

 No. V. 



(NOTHOLCA SPINIFERA.) 



OF the Rotifera the great majority of species 

 belong to fresh water, and until recently com- 

 paratively few species were known to us to inhabit 

 the sea: but since 1885 there have been no fewer 

 than twenty new species' added to the list as belong- 

 ing to a marine habitat, and N. spinifera is one of 

 them. It belongs to the sub-order Loricata, family 

 Anurreadse, and has been classified by Mr. Gosse in 

 genus Notholca. 



It is an attractive and interesting Rotiferon. Its 

 body is protected by a purse-shaped lorica (or 

 sheath) of a horny consistence, and is divided into 

 two plates by a deep wide cleft on each side. The 

 dorsal is striated and rather less than the ventral 

 plate in adult individuals, but in young the dorsal 

 and ventral plates are equal. The front of the lorica 

 on the dorsal side is furnished with six spines like 

 the teeth of a saw of irregular length, the two centre 

 ones being the longest. 



The chief peculiarity of the N. spinifera is the fact 

 that it is provided with a pair of articulated spines, 

 one on each side, projected and folded at the will 

 of the animals by a pair of muscles. The function 

 of the lateral spines is undoubtedly as organs of 

 defence, as the creature is observed to extend the 

 spines on the least approach of danger. The 

 muscles and the nature of the joint are best observed 

 when one or two individuals are secured in a com- 

 pressorium and examined by a power of three- 

 hundred diameters. From the irritation caused by 

 the cover glass, the animal when in this position is 

 continually extending and retracting its lateral spines, 

 and thus the expansion and contraction of the muscles 

 are very well seen ; and the phenomenon is extremely 

 interesting to the observer. The hinge of the spines 

 seems to be a ball and socket joint, which forms a 

 junction between the dorsal and ventral plates. In 

 the cleft on each side, the lateral spines are concealed 

 when retracted, and only visible when projected. 



The N. spinifera has a large stomach usually filled 

 with brown matter, but the colour depends on the 

 nature of the food within the creature's reach. Its 

 food consists of both animal and vegetable organisms. 

 It feeds on infusorians, spores and antherozoids of 

 algoe. 



It is furnished with a pair of powerful jaws, which 



