368 SUMMARY OF CURRENT RESEARCHES RELATING TO 



following rotifers were abundant in the lake of Egedesminde : — Triarthra 

 longiseta Ehr., Asplanchna helvetica Im,, Anursea coclilearis Gosse, 

 A. longispina Kell., ConocMlus volvox (?). These are new additions to 

 the Greenland fauna. The fauna of the Greenland fresh-water basins 

 resembles in several ways that of Europe, but differs in the presence 

 of special types. 



B. INVERTEBRATA. 



Excretory Organs.* — Prof. A. Kowalevsky has made an investigation 

 into the structure of excretory organs of animals, which he has fed or 

 injected with various colouring matters ; the organs were then examined 

 fresh, or treated with alcohol and cut into sections. 



Beginning with the Crustacea he injected into a crayfish a 1 per 

 cent, solution of carmine and ammonia ; after some hours he found that 

 the terminal saccules of the anteunary gland began to colour, and 

 gradually become more and more red; in the course of two or three 

 days the coloration reached its maximum. The nuclei of the cells 

 remained quite normal and white, as only the granules took up the red 

 colouring matter ; at the ends of the cells which were directed towards 

 the lumen of the gland the granules became collected into small masses ; 

 these separated from the cell-substance and fell into the lumen of the 

 gland. Different results were attained when indigo-carmine was used. 

 It was, in effect, found that Weismann and Grobben are right in com- 

 paring the terminal saccules with the Malpighian capsules, while the 

 urinary canaliculi of Astacus and of the Vertebrate kidney correspond to 

 one another in relation to indigo-carmine. From these experiments and 

 from others with other colouring matters, it may be concluded that in 

 the antennary gland of the crayfish there are three divisions which are 

 physiologically distinct; — the terminal saccules with acid reaction, the 

 commencement of the urinary canaliculi where indigo-carmine is excreted 

 and the reaction is alkaline, and a third portion, the white loop, which 

 for a long time remains indifferent to the staining materials; where 

 large quantities are used for some time small quantities of indigo 

 carmine are deposited in it. Various other Crustacea were experimented 

 with, and it was found that in the shell-gland of the lower forms the 

 terminal saccules and the urinary canaliculi have the same functions as 

 in the antennary gland. 



A number of observations were made on Insects and it was found 

 that, in comparison with Crustacea, the function of the antennary or shell- 

 gland is so far separated that that of the urinary canaliculi is performed 

 by the Malpighian vessels, while there is no organ corresponding to the 

 terminal vesicles ; their function is performed by the pericardial cells. 

 The author has already shown that these have the office of purifying the 

 blood and extracting from it foreign or dangerous bodies ; the action of 

 these cells may be compared to that of phagocytes, as they have no 

 efferent ducts. 



Numerous representatives of the Mollusea were examined, and it was 

 found that the indigo-carmine was secreted by the same elements as 

 those which secrete the renal salts, for the colouring matter was deposited 

 not only in the same renal cell, but in the same vacuole as the urinary- 

 concretions. We may conclude, therefore, that in the Mollusea there 



* Biol. Centralbl., ix. (1889) pp. 33-47, 65-76. 



