HARD WICKE ' S S CIE NCE - G SSI P. 



149 



five-jointed, and the abdomen variable in shape and 

 consisting of eight or nine segments. 



5. Echinophthirius. There is only one species of 

 this genus, viz. that found on the seal (see Fig. 96), 

 which has been classified by some as a Haematopinus ; 

 the antennce however are only four-jointed. 



6. Haematomyzus consists of only one species (see 

 Fig. 97), which infests the elephant. This species is 

 easily distinguished by its long fleshy haustellum, 

 which is terminated by barbs like the Ixodes. This 

 structure of the mouth is evidently a necessity for the 

 parasite's existence, as without the long barbed 



Fig. 96. — Echinophthirius 

 of Seal. X 60. 



Fig. 97. — Hsematorrryzus of 

 Elephant. X 20. 



Fig. 98. — Docophorus of 

 Rook. X 60. 



Fig. 99- — Nirmus of Oyster- 

 Catcher, <$ . X 60. 



haustellum it would never be able to pierce the thick 

 hide of the elephant. 



We now come to the second of our large divisions, 

 subdivided into two families, which are distinguished 

 by the structure of the antennae. In the Philopteridce 

 the antennce are filiform, in the Liotheidce clavate- 

 The Philopteridce are divided into two distinct 

 classes, the first having the antennce five-jointed and 

 the second three-jointed. 



1. Docophorus. — This is perhaps the most plentiful 

 of all the species, and is distinguished by the presence 

 of trabeculce, i.e. small movable organs immediately in 

 front of the antennae. The only genus likely to be 

 confused with this is the next : — 



2. Nirmus. — Some of the Nirmi have trabeculce 



like the Docophori, but generally of smaller size. 

 The chief difference however between the two 

 genera is that in the latter the species are nearly 

 always much more slim than in the former, and the 

 head not so broad at the base. 



THE NATURAL PRESERVATION OF ROTI- 

 FERA AND OTHER POND ORGANISMS. 



By E. B. L. Brayley. 



LOVERS of pond life must continually regret the 

 paucity of published information on the natural 

 and permanent preservation of the various organisms 

 found by them in their gatherings. And when some 

 specially rare form has been found, half the joy 

 caused by the find is dissipated by the knowledge 

 that in a general way it cannot be relegated to the 

 safe custody of the cabinet for future reference and 

 exhibition, but must be gloated over whilst it lives, 

 as very probably the observer may not again come 

 across a similar form for many years. Besides which 

 the veracity and the genuineness of the find may be 

 impugned by a jealous and less fortunate confrere. 

 The following notes may therefore be of interest to 

 some of the pond-hunting readers of Science-Gossip, 

 and I feel sure, if some other workers also published 

 the results of their labours, valuable formulae would 

 be discovered, and much fresh information would 

 accrue. Whilst specially experimenting on the 

 Rotifera and Infusoria, I have also tried most of the 

 organisms met with in general gatherings. Any weak 

 point in the formulae I shall point out, in the hope 

 that some reader may be able to overcome the 

 difficulty. 



Rotifera. — By the aid of the annexed (I think 

 original) formula, I have been enabled, amongst others, 

 to mount the following forms : Melicerta, OZcistes, 

 Stephanoceros, Asplanchna, Synchceta, Eosphora, 

 Scaridium, etc., the tube-dwellers all fully extended 

 from their tubes, and the others with cilia exserted in 

 a natural manner. In the transparent forms the 

 internal structure can be easily studied. 



Chromo-salicylic solution. — Chromic acid, 2 grains j 

 Saturated aqueous solution of salicylic acid, \ oz. ; 

 distilled water, 1 oz. Add about two drops of the 

 above to each teaspoonful of the water containing 

 the rotifers. Its action should be very slow, taking 

 six or more hours to kill, the animal swimming about 

 as usual for some time. If too much be used the 

 rotifer at once doubles up, swells, and is useless. 

 The water should hardly be perceptibly tinted. 

 Mount in the same water in which the creature is 

 killed. It is preservative as well as fixative. With 

 muddy water, transfer rotifer to clean before adding 

 solution. With Floscules it is advisable to fix in same 

 cell they are intended to be finally mounted in, as 

 moving disarranges the setae. To study internal 



