96 



contain much pigment, was dried in an exsiccator and weighed. 



The quantity of fat present in two large, freshly caught spe- 

 cimens, proved to be 103 mgr. But 51.5 mgr. of fat per starfish 

 seems to be an exceedingly small quantity, especially when 

 we take into consideration that part of it may have been 

 pigment. 



In Holothurians also Putter 1 05) found a very small quantity 

 of fats. According to his figures 0,014 "/o of the wet weight 

 of Cucumaria grubei consists of fats and lecithins. This means 

 that in an average specimen of this fairly large species 203 

 mgr. of these substances are present. This figure is also very 

 low and might represent only the lecithins of the nervous 

 system and some pigment. It need not be mentioned that in 

 our figures the lecithins, of course, are also included. 



A second group of reserve substances are the carbohydrates, 

 generally represented in the animal kingdom by glycogen. This 

 substance present in almost all invertebrate groups, is wanting 

 in starfishes. To make sure of this I treated several sections of 

 the radial sacs of these animals, made in the usual way — al- 

 cohols, paraffin — with J in KJ, after the parafBn had been 

 dissolved away with xylol, the xylol replaced with alcohol 

 and the alcohol with water. Whereas in many other invertebrate 

 groups, as f. i. in snails — see Biedermann and M o r i t z 9) ^ — , 

 the „liver" contains an abundance of glycogen, so that every 

 section immediately shows the typical glycogen reaction, nothing 

 of the kind occurs here, the reagent failing to give any indi- 

 cation of the presence of glycogen. Krukenberg also sear- 

 ched in vain for glycogen in the starfishes '). 



A similar test was made on the guts of Thyone fixed in 

 several different ways. Here every section gave a strongly 

 positive test. This explains at the same time the nature of 

 the ..insoluble carbohydrates" found by Piitter 105) in his 

 Holothurians. Not less than 15.8 "/q of the dry ,weight of his 

 Cucumaria is insoluble carbohydrate. 



"A third class of reserve substances are the proteins. We find 

 protein crystalloids in many invertebrates of different groups, 

 from the flat worms (Saint-Hilaire 113)) up to the highest 

 and in many cases they have been considered as reserves. 

 These protein crystalloids are also found in Echinoderms. They 

 occur in the amibocytes (Wanderzellen) of the sea-urchins, where 

 they were discovered by C u e n o t 23). In the same cells we find 

 numerous grains of pigment. These pigments are produced, accor- 



') Stone 125) also failed to find glycogen in the starfish radial sac; she 

 extracted them by means of Pfliiger's method and did not obtain any evidence 

 of its presence. 



