100 BALANOGLOSSIDA. 



such as the presence of eye-spots and an apical plate, does not 

 nullify this resemblance and renders it extremely probable that 

 the Enteropneusta have affinities with the Echinodermata as 

 well as with the Vertebrata a view which is expressed in this 

 work by the juxtaposition of the chapters dealing with them. 



The Balanoglossida live in sand or mud* and are found in most 

 seas. Their burrows, the walls of which appear to be cemented 

 into some consistency by the mucus which the animal secretes, 

 appear frequently to be U-shaped, opening on the surface at two 

 points. At one of the openings the casts formed by their faeces 

 are discharged, while the anterior end is in relation with the 

 other opening. In Dolichoglossus kowalevskii, Bateson describes 

 them as being highly coloured (collar a bright orange) and as 

 living at about a depth of eight inches with the anterior end 

 of the body (to the branchial region) and the hind end 

 both vertical, the middle portion being coiled in a corkscrew 

 spiral. 



They usually possess a disagreeable smell, described as re- 

 sembling that of iodoform or sometimes that of chloride of lime 

 with a faecal admixture. 



It frequently happens that two species live in association : 

 thus Willey records that Glossobalanus ruficollis inhabits the same 

 burrow as Bed. carnosus in New Britain, while the latter is taken 

 with Spengelia porosa at Lifu. They actively burrow in the 

 ;sand by means of their proboscis and collar, in which the chief 

 muscular development occurs, drawing the hinder part of the 

 body passively after them. The proboscis and collar can be 

 readily rendered turgid or the reverse, and they clear out the 

 sand and mud by swallowing them. Thus their locomotion and 

 alimentation are effected by the same means. It is probable 

 that the inflation of the proboscis and collar which appears to 

 be a necessary condition of their use in locomotion is effected 

 by the taking in of water through the proboscis and collar 

 pores. 



The body very readily breaks into pieces particularly the 

 hinder part, and some species appear to be able to practise 

 autotomy. In presence of this fragility of body, we should 

 expect the power of regeneration to be considerable, and this 

 appears to be the case. Animals are frequently taken showing 

 * See, however, note on p. 103. 



