20 



GENERAL FEATniKS, IMETIIODS, ETC. 



ha):)its or an adaptation for a lifo in tho bottom ooze. In Chaetoderma the ali- 

 mentary tract is a comparatively simple tube passing directly through the body, 

 (as with other Solenogastres), provided with a radula, reduced to a single median 

 tooth, and a voluminous unilobed liver. In other genera (Prochaetoderma, 

 Limifossor) of the family the radula is of large size, and is typically formed and 

 placed. In the Neomeniina this system is more complex. The first division 

 of the digestive tract, which may be termed the atrium, probably corresponds 

 to a highly modified buccal plate, and though usually connected with the mouth 

 (Diagram p. 20, A) may be separated from it. The walls are modified into 



Diagrams illustrating structure of a neomenian. A aniiiior < nd b briui, ilsg dorsal salivai'y 

 gland; f foot; gon gonad; im, om inner and outer atrial ridges ondosuig the iniose arei,, uit stomach- 

 intestine; s subr.adular organ; sg ventral salivary gland. B posterior end. el eloacal caMty; cp dorsal 

 limb of gonodurt; do dorso-terminal sense organ; pom pericardium; r seminal receptacle; sgl ventral 

 limb of gonoduct or shell gland. 



ridges and cirri, probably sensory structures. A radula is generally present 

 though often greatly reduced in size. In addition to the dorsal salivary glands, 

 probably existing in certain Chaetodermatina as well, a ventral pair is usuallj' 



