204 GRIFFIA. 



Mesonemertini. 



3. Carinoma mutabilis n. sp. 



Color a pure creamy or milky white, with faint cloudy mot- 

 tlings in intestinal region, which cease a short distance from the 

 posterior extremity, leaving the tail region pure white. 



Length • and breadth variable, the largest 

 individuals of the type measured 14 cms. 

 by I mm. in alcohol. 



Head hemispherical, narrower than body 

 and marked off from latter by a slight nar- 

 rowing or neck. No eyes or caudal cirrus. 

 Internal Anatomy. This species ap- 

 proaches very closely the C. patagonica 

 Biirger('95). It appears to differ, however, 

 in several particulars, especially in size and 

 in the disposition of the nephridial tubules. 



Fig. 16. Carinoma intita- ,^, , , i 1 1 -r 1 



/>///> n.sp. I. Two in- ^^^^ ^^^^^^' ^^'^ ^^^g^ ^"<^ looscly ramified, 

 dividuals of type. II. but three or four cross sections of them 

 variety ^r^////;/.7. Cam- appear in each section and, although some 



era lucida from aico- r -li 1 1 -^ .l 1 1 "^ ^ ^1 



, ,. , . , 01 the branches are situated close to the 



nolle material. 



blood vessels, they do not appear to bulge 

 into them to the extent that they do in C. patagonica. They 

 open to the exterior by a single-paired excretory pore, the posi- 

 tion of which varies in different varieties, though always dorsal 

 to the nerve-cords. Circulatory system in its main features as 

 in C. patagonica. Ventro-lateral blood vessels thick-walled, 

 thickness of which steadily increases as nephridial region is 

 reached. This peculiarity can be traced throughout the 

 nephridial region.^ Dorso-lateral vessels thin-walled through- 

 out. Dorsal and ventral nerv^es anteriorly outside the outer 

 circular muscle-layer. A double diagonal muscle-layer com- 

 mences to appear in the anterior oesophageal region. 



Inner circular-muscle-layer much thicker anteriorly than in 

 C. patagonica. 



1 Compare similar phenomenon figured by Mcintosh ('75). 



