Dixon — On Two Irish Specimens of Edwardsia timida. 101 



ally undergoing changes of form, being sometimes flat, sometimes 

 raised into a pointed cone, with the lips protruded and folded hack. 

 (3) Quatrefages makes the consistence of the investment a further 

 ground of distinction. Andres, however (/. c, p. 93), refuses to 

 give any weight to such a matter as this, as a specific distinction 

 among the Edwardsidae, considering that the nature of the invest- 

 ment largely depends on the environment of each individual. In 

 connexion with this question, too, it should he borne in mind that 

 Quatref ages found the one example on which he rests his E. harassi 

 in a different locality from where he found the specimens which he 

 referred to E. timida. (4) Lastly, E. timida measures 6-7 cm. in 

 length, while E. harassi only measures 5^ cm. This would not 

 appear to me to be an important difference, but merely to depend 

 on the temporary elongation or contraction of the animal. 



Quatrefages referred all Edwardsidae to one genus, Edwardsia. 

 Andres has constituted two genera in the sub-family, reserving the 

 name Edwardsia for all such species as have sixteen tentacles, and 

 classing under the name Edwardsiella all those that have twenty 

 or more tentacles, including, of course, the E. timida and E. harassi 

 of Quatrefages. In the present state of our knowledge no advan- 

 tage would seem to follow from multiplying the genera, and there- 

 fore I have adhered to the nomenclauture of Quatrefages. My 

 two specimens evidently belong to the same species, but as they 

 differ somewhat from one another, I have described both. All the 

 features in the following description are common to both specimens, 

 except where a separate description is given of each under the 

 several designations of a and )3. 



Description. 



Form. — Column thin, very much elongated ; divided into 

 physa, scapus, and capitulum. 



Physa — delicate, smooth, retractile within the scapus ; when 

 fully distended exceeding the scapus in diameter, and sometimes 

 rising from it by an abrupt step ; studded with minute suckers ; 

 divided into eight segments by eight lines, which correspond with 

 the insertions of the mesenteries ; no terminal pore is present. 



Scapus — long, slender, vermiform, slightly tapering towards 

 either extremity, cylindrical, smooth, without tubercles or longitu- 

 dinal ridges or furrows ; clothed with a transversely corrugated 



