206 GRIFFIN. 



Habitat and Distribution. Between tides in hard blue 

 clay among pholads, not apparently in burrows of latter, but 

 in surrounding clay, to all appearances excavating burrows of 

 its own.^ Locality, w^est of Point Wilson on shore of Strait of 

 Juan de Fuca. 



5. Carinoma mutabilis vasculosa n. van 



Form and color as in type, size intermediate between type 

 and var. argillina. Mesenchyme most extensive, in oesophageal 

 region nearly surrounding the very large blood vessels. Ventro- 

 lateral vessels branch from time to time. Excretory pore at 

 commencement of visceral region where inner circular-muscles 

 thin out. 



Habitat and Distribution as in type, except that it was not 

 taken on pile's. 



All these varieties build sand-tubes and in mode of life re- 

 semble somewhat Ccrcbratiihis, though they do not swim nor 

 readily fragment themselves as do the cerebratulids, and appear 

 generally more sluggish. 



Analytical Key to Species of Carinoma. 



A. — Nerve cords anteriorly without circular muscle layer ; further 

 back they break through the latter, and lie wholly within longitudi- 

 nal layer C. armandi (Mcintosh) Oudemans, 



B. — Nerve cords wholly within longitudinal layer throughout their 

 entire course. 



« — Small (3.5 cms.). Brain free in longitudinal muscles of head. 

 Nephridia bulge far into thin-walled blood vessels. Dorsal and ven- 

 tral nerves wholly within outer circular-muscles-layer throughout their 

 entire course C. patagonica Burger, 



/5 — Large (14-15 cms.). Brain enclosed in connective tissue cap- 

 sule. Nephridia do not bulge so far into the thick-walled blood 

 vessels. Dorsal and ventral nerves anteriorly without outer circular- 

 muscle-layer; further back break through same... C. mutabilis Mihi. 



^If this be true, the fact is interesting because of the soft-bodied nature of the 

 animal. The annelid Halla ? is knovVn to bore in the till ( Harrington and Grifhn,^ 

 '96), but this animal, unlike the Nemertean, has powerful jaws and a firm exo- 

 skeleton. Heretofore no Nemertean has been known to bore in so hard a substance 

 (Mcintosh, '68). 



