40 



PART I. GENERAL ACCOUNT 



Fig. 28. Pyriform gland of Lamellisabella zachsi from the metasomal region, after staining for 



polysaccharides. 



cut - cuticle; dgt - duct of the gland; pgt - pore of the gland; se - granular secretion; 5/- lamellar 



secretion. (After Ivanov, 1960a.) 



The granular secretion of the flask-shaped glands gives a positive reaction 

 for polysaccharides in the periodic acid-Schiff test (Fig. 28), i.e. it displays 

 the same chemical nature as the substance of the tube (p. 122). Polysaccharide 

 is unevenly distributed in the laminar bodies, forming a thin envelope over 

 the surface of each of these bodies and penetrating into its interior as fine 

 veins which tunnel through the otherwise homogeneous substance (Ivanov 

 1960a). 



A large number of flask-shaped glands is concentrated in the coelomic 

 sacs of the mesosoma (see PI. Ill, facing p. 92), but in Siboglinum caulleryi 

 they are not numerous in this region but confined chiefly to the hind part of 

 this segment. In the Thecanephria the main mass of glands lies in the 

 coelom of the metasoma. In the front part of the trunk they are particularly 

 numerous, while in the nonmetameric part of the metasoma they are en- 

 countered more rarely, since they are apparently ousted by the strongly 

 developed genital organs. In front of the girdles their number increases once 

 more and finally there are many in the postannular region. 



