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CLASS LABYRINTHULIDEA. 



Rhisopod Protozoa (?) with filamentary tracks and travelling spindles. 



A group Labyrinthuleae was established, in 1867, by Cienkowski for 

 the reception of L abyrinthula, an organism discovered by him growing upon 

 piles in the harbour of Odessa. A somewhat similar organism, Chlamydo- 

 myxa, has been found by Archer in Westmeath and Connemara, infesting 

 the leaves, &c. of Sphagnum and other freshwater plants ; it has also been 

 recently observed by Ray Lankester at Pontresina in the Engadine. 



There are two species of Labyrinthula, L. vitellina and L. macrocystis. 

 The former lives at the level of the watermark, and in the resting condition 

 appears as reddish-yellow masses about the size of a pin's head. If such a 

 mass is placed in water for twenty-four hours, it passes into a motile 

 condition ; and when examined under the microscope, is seen to consist of 

 a central mass whence there extends towards the periphery of the drop of 

 water an open network of filamentary tracks. Moving along these tracks at a 

 rate of about ^V-^V mm - P er minute are yellow spindles which collect 

 here and there into outlying groups. The central mass consists of a 

 finely granular matrix imbedding numbers of yellow or brick-red globular 

 cells -012 mm. in diameter, with a nucleolated nucleus and an envelope 

 which stains brown with Iodine. When fresh they are stained blue by 

 the same reagent. These cells assume a spindle-shape and wander from 

 the central mass, which undergoes meanwhile no visible change along the 

 filamentary tracks, as above stated, until in a few hours' time they have all, 

 or at any rate the majority of them, quitted it. They multiply by binary 

 fission. The filamentary tracks are glassy in appearance, homogeneous or 

 fibrillate, rigid and unchanging ; whether tubular or composed of fibrils 

 lying at some distance apart, Cienkowski could not determine. Whatever 

 their nature, they appear to consist of the same substance as the matrix 

 of the central mass, not protoplasmic, but rather a secretion. Cienkowski 

 states that after the wandering of the spindles is completed, the tracks 

 become invisible in some places, in others, where there are isolated spindles 

 or masses of spindles, gelatinous ; that individual spindles or naked 

 spindle-masses are capable of forming tracks, and that when the organism 

 grows under water the amount of matrix is greatly increased. The motile 

 condition of the organism was found naturally existing among the colonies 

 of Campanularians and on the eggs of Tergipes. 



L. macrocystis lives at some distance above the watermark. It differs 

 from the foregoing species in the following particulars. Its resting-phase 

 has the form of yellowish or white vermiform masses. Its cells are larger, 

 018025 mm - in s i ze > their nuclei more sharply defined, their contents more 

 granular, colourless or -feebly yellow, and not stained blue by Iodine. It 



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