34 



Drs. J. H. Ashworth and T. Rettie. 



[Sept. 28, 



The protcmierite is narrowed in front into a neck-like region, which hears 

 the epirnerite, hut the " neck " is usually short, and it is very short in the 

 case of specimens lying free in the gut. The protomerite and deutomerite 

 together form a mass which, in the smaller trophozoites, is usually oval, 

 or, in some cases, nearly spherical, but in the largest examples is almost 

 pear-shaped (fig. 8). 



These two regions are separated internally by a thin septum, but the 

 external surface does not bear any well-marked groove indicating the line 

 of separation. In the few cases in which an external groove was present, 

 it was faint. The septum is seldom equatorial in position ; it is generally 

 nearer the epirnerite.* Below the thin epicyte (cuticle) there is a peripheral 

 layer of ectoplasm 2 to 3 /j, in breadth, which is clear, as it contains few 

 •granules. This layer is thicker at the distal end of the deutomerite. The 

 protoplasm of the " neck " is generally homogeneous, like the ectoplasm. 

 In this region faint longitudinal stria?, probably myocyte fibrillar 

 (myonemes), are present (fig. 9). Such striae were not observed in other 

 portions of the Gregarine. The endoplasm is very fluid, and contains 

 numerous grey, refringent, nutrient granules, the largest of which are about 

 2 ^ in diameter. Granules are much more abundant and coarser in the 

 ■endoplasm of the deutomerite than in that of the protomerite. The nucleus 

 is invariably situated in the deutomerite. In the fresh condition it is a 

 clear vesicle with regular outlines, and contains from one to four karyosomes. 

 The latter are usually homogeneous, but sometimes they are vacuolated 

 {figs. 4, 5, 9), and in several cases they were observed to contain spherules 

 of more refringent nature (fig. 6), composed of denser chromatin. 



The Gregarines generally occur in considerable numbers ; in one case 

 75 were present in the mid-gut, but they are not found in pairs, except at 

 the moment of encystment. 



When full grown the Gregarines become associated in pairs, preparatory 

 to the formation of gametes. We have made numerous attempts to obtain 

 the early stages of this association, but in the youngest met with the 

 organisms had formed the common cyst wall, and the peripheral protoplasm 

 of each individual was already raised into the rounded masses, which would 

 soon have become gametes. We conclude that the association of the two 



* We have seen a considerable number of trophozoites of various sizes up to 40 \x in 

 length, in which the epirnerite was wanting. These were lying free in the cavity of the 

 inid-gut. They were ovoid in form (fig. 2, B), and the septum was almost invariably 

 absent. Whether such specimens can subsequently develop a new epirnerite, and 

 re-attach themselves to the gut-wall, was not ascertained with certainty, but it appears 

 probable that the smaller ones, at any rate, may do so. 



