some neio Species of Drawida. 499 



species of Draivida examined and described in this paper. 

 Conmieueitig from behind the hist gizzard, there are a pair 

 of these finger-shaped organs occurring in each segment 

 in various degrees of development. A reference to these 

 structures has rarely been made by previous authors, who 

 have described about forty and odd species belonging to 

 this genus. The mode of development of these organs is 

 best studied in young worms, such as those of 1). parudoxa, 

 in which they occur in the middle and hinder portion of the 

 intestine in an inci[)ient stage. Tiie dorsal muscle-fibres 

 (PI. XVI. fig. 4) of the alimentary canal^ at the points Avhere 

 the glands are developing, are laid or become disposed like 

 the ribs of a fan, and are comparatively shorter than the 

 neighbouring fibres, which are certainly longer and are cir- 

 cuhnly disposed. In the middle of each of the former set 

 of fil)res a swelling takes place, due to the aecnmuhation of 

 lymph and lymph (coelomic) corpuscles. At the point 

 where these specialised muscle-fibres, which ultimately 

 change their muscular character, converge on the inner 

 border towards the dorsal vessel, there is a dense heaping up 

 of cells proliferating from the peritoneum. From this 

 source, these rapidly multiplying cells move outwards across 

 the metamorphosing muscle-fibres, becoming at the same 

 time incorporated with the coelomocytes. The number of 

 muscle-fibres affected at the beginning may be between 24 

 and 36, out of which about 6 to 12 may reach the final 

 stages of glandular development, while the others are detect- 

 able in a state of arrested growlh. A fully formed glandular 

 process thus derived from a muscle-fibre uniy attain a size 

 nearly over fifty times that of the latter, I could discover 

 no peritoneal covering on the digitate processes or on the 

 basal lobe, even in sectional preparations, and there is no 

 other connection between these stuctures and the septa 

 beyond a few muscle-fibres. Both morphologically and 

 perhaps physiologically, too, these enieric appendages of the 

 species of Drawida described here would appear to be 

 distinct from the "lymph glands '^ of Schneider. 



It is noteworthy that these structures are best developed 

 in forms taken in places rather dry and exposed. Each of 

 these appendages, looking white and disposed in the form 

 of tubules, is attached to the dorsal vessel partly by its own 

 connective tissue, but maiidy by an arterial twig on either 

 side. This is the principal source of blood-supply to them, 

 and histologically they are mesoblastic in origin. When an 

 entire appendage is cleared by acetic acid, and examined 

 microscopically under the high power, more than two kinds 



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