Introduction to A ninial Morphology. 1 8 1 



from the body wall, to which it may be suspended by 

 mesenteric strings. Little spines sometimes arm its 

 oral end, even in embryos (Enoplus and Anguillula), 

 In Ascaris megalocephalus there is a gland in the 

 oesophagus opening outwardly. In Cheiracanthus 

 aculeatus, of the tiger, four caecal (salivary r) glands 

 open into the mouth ; while a lining of gland-cells in 

 the oesophagus is not uncommon. In some, the 

 oesophagus acts as a sucking tube, and is divided into 

 a glandular and a suctorial part. The so-called 

 stomach is distinct, muscular, often globular, some- 

 times with a chitinous, gizzard-like lining, and may 

 be suctorial, the true stomach then being the dilated 

 •end of the straight intestine, into which this gizzard 

 opens by a narrow pylorus. The intestine has a 

 glandular lining, a muscular coat (for its lower third 

 only in some), and it is held in its place by thick, in- 

 terrupted, cellular mesenteries, the appendices nour- 

 ricieres of Cloquet. The anus is ventral, longitudinal, 

 sometimes sub-terminal or terminal (Trichina, Tricho- 

 oephalus), absent only in one family ; glandular caeca 

 often occur in the course of the intestine. Anguillula 

 appendiculata has one from the intestine, Asc. hali- 

 coris from the stomach. The body cavity contains a 

 perivisceral fluid (blood r), in which a few oval and 

 amoeboid corpuscles float. A water-vascular canal 

 lies in each of the thick lateral lines of the dermis ; 

 these open by a common medio-abdominal pore, 

 usually at the level of the muscular stomach. They 

 are seldom absent, branched in Strongylus auricularis, 

 and forming a ribbon-like lateral organ in Filaria. The 

 four circum-anal caeca in Ascaris dactyluris, which 

 open by narrow ducts within the anus, may be excre- 

 tory organs, possibly renal. 



