344 HARMOTHOE LUNULATA. 



beyond the bases of the nearest bristles. They have the same sparsely distributed short 

 cilia. 



Habits. — Earmothoe lunulata is a very active species amongst the laminarian roots, 

 and displays as much irritability as Evarne impar. It is also sometimes found as a 

 commensalistic form in the tube of Poly cirrus. It is brightly phosphorescent, glowing 

 when irritated at the bases of the feet for a considerable time, and giving off flashes 

 when immersed in spirit, as well as generally breaking in pieces. 



The Zetlandic examples of the species are somewhat elongated, have longer feet, and 

 longer and more delicate pale bristles ; moreover the dorsal and ventral cirri are longer 

 than in the southern forms. 



It is evident that the species approaches E. marphysx very closely, though the cirri 

 of the latter are shorter and smoother, the bristles of the dorsal branch much shorter 

 and less conspicuous, and those of the ventral division shorter and more slender. More- 

 over those of the superior ventral series have no bifurcation at the tip, the closest 

 approach to the latter condition being in a variety of E. lunulata from St. Peter Port, 

 Guernsey, which had an indistinctly bifid tip in one or two of its superior bristles. 



I have united it, after Claparede, with Delle Chiaje's form, though in his original 

 description of the species he gave it a single caudal style and fourteen pairs of scales- 

 characters also illustrated in his somewhat stiff figure, which shows the middle line of the 

 dorsum quite bare from end to end. 



Claparede, who studied the species at Naples, correctly described it as having fifteen 

 pairs of scales, and pointed out the pinkish hue of the ventral median line anteriorly— 

 from the nerve-cord — on which he found no ganglia. He gives the total number of 

 segments as thirty-seven, and shows that the last bears two large terminal cirri. At the 

 bases of the feet are vibratile rosettes as described by Bhlers, and they are about four in 

 number. In the preserved examples the two whitish masses he mentions on the feet 

 are not visible. He also notes the apparent absence of blood-vessels, and describes the 

 nerve-cord as having a median and two lateral bands corresponding to the nerve-cells, 

 of which he gives some further details. He is of opinion that Costa's P. tessellata is the 

 same species. He describes the scales as finely granular and without horny papillae, but 

 in his figure the greater part of the surface (all but the anterior third) shows such 

 papillas. This, therefore, is a point on which further evidence is required, especially as 

 the distribution of these horny papilla in the British examples is so well defined. 

 Should the evidence prove that the Mediterranean form is different, then Dr. Carrington's 

 name, E. maculosa, stands. Ife first found the species in this country stranded on 

 Southport sands. 



Prof. Panceri l experimented with this species and others in regard to luminosity, and 

 came to the conclusion that it emanates entirely from the scales, and that it is connected 

 with the remarkable terminations of the nerves in the subcuticular granular layer of the 

 epiderm. 



Grube's P. maculata 2 seems to be an allied form, but the description of the cirri 

 differs. 



1 ' Atti B, Accad. di Napoli,' 1875, p. 13, Tav. 304. 

 Actin., Echin., u. Wiirm./ p. 87, 1840. 



2 f 



