Tribus Ægireæ. 1 ) 
Actinida, with a perfect body-cavity (Coelome) and a developed 
digestive apparatus, consisting of oesophagus, intestine and anus. 
Family JEgiridæ* 
Ægireæ, whose body is cylindrical, vermiform ; 1 2 single sep ta 
with the Coelome divided into 12 longitudinal chambers. 
Genus Fenja. 2 ) 
The body cylindrical, elongate; furnished with 12 longitudinal 
grooves, between which 12 longitudinal areas covered with suckers. 
A series of a few retractile tentacles. Anus. 12 perfect septa. 
12 longitudinal muscles; between which strongly prominent trans- 
versal muscles. 12 genital pores around the anus, outside the 
rectum. Mesodermal circular-muscles. Hermaphrodite. 
Fenja mirabilis* 
Pl. r. fig. i— 14. 
The body is cylindrical; 70 m. m. in length, and 15 m. m. in 
breadth at the anterior extremity, whilst the posterior part is rather 
narrow, partly rounded, and partly conically acuminated, according 
*) Ægir — The God of the sea in Scandinavian mythology. 
2 ) Fenja — A sorceress of the Jotun race, dwelling in the depths of the sea, 
occupied in grinding salt. (Scandinavian mythology.) 
I* 
