MOLL use A OF I'LYMOUl'H. 435 



tiiiguish this species from its allies. lu general appearance this 

 specimen much, resembled an ^. Alderi. 



Suh-family 2. — Cratenin^. 

 19. Ckatena, Bergh. 

 2i. Cratkna viRiDis, Forhei^. 



MONTAGTJA viElDis, Forhes. Ann. Nat. Hist., v, 1840, p. 106. 



EoLis VIEIDIS, Forhes. Alder and Hancock, Monograph, Fam. 3, pi. xxxii. 



— GLOTTENSis, Alder and Hancock. Monograph, Fam. 3, pi. xxix. 



— AEENICOLA, Forbes, MS. Alder and Hancock, Monograph, Fam. 3, 



pi. xxxi. 



— NOETHUMBEICA, Alder and Hancock. Monograph, Fam. 3, pi. xxxi. 



Four individuals of this species have been taken. One small one 

 was dredged on September 24th, 1889, in about ten fathoms water, 

 a quarter of a mile south-south-east of the Mewstone, on weedless 

 ground. It was found by Mr. Bourne creeping on a mass of 

 Lepralia foHacea. It possessed nine transverse rows of cerata, the 

 first half-row consisting of two very small cerata, the second half- 

 row of three, the third and its successors of four, while the eighth 

 and ninth half-rows consisted of three and of two cerata respectively. 

 The four anterior rows were set closely to one another, and were 

 separated by an interval from the posterior rows, which were placed 

 behind each other at regular distances. The hepatic caeca were very 

 dark green in colour, and all the tissues were permeated with a 

 green tinge. 



The second specimen, of the same size and colour, was dredged on 

 similar weedless ground in October. 



The third was considerably larger, and was found among Polyzoa 

 and Hydroids by William Koach inside the Sound during the first 

 week of November. 



The fourth was a very young individual, dredged near the Duke 

 Rock on a stone covered with Eudendrium capillare, February 18th, 

 1890. The colour — a greenish yellow — was confined to the hepatic 

 caeca. The cerata were as contractile and muscular as the tentacles. 



The three " species," gJottensis, arenicola, and northumhrica, de- 

 scribed in Alder and Hancock's Monograph, appear to be merely 

 slight varieties or different stages of Cratena viridis. Only a single 

 example of each type has been recorded. Our first specimen was 

 undoubtedly of the same species as the type of glottensis, but differed 

 from it in not having the tips of the cerata orange-coloured, nor 

 were the rhinophores thickened at the tip. Eolis arenicola may be 

 distinct, but Forbes's specimen was probably an exceptionally large 



