202 Copepoda living as Parasites or Messmates. [Sess. 



the species being really " new." The discovery of one or two 

 females with ovisacs, however, removed some of the doubts we 

 had concerning the genuineness of the species ; and a descrip- 

 tion of it, with figures, was published in the 'Annals and 

 Magazine of N"atural History' for March 1893. Though the 

 structure of the mouth-appendages of Parartotrogus indicates 

 parasitic habits, we have not ourselves been able to locate the 

 host on which it lives ; but Dr Giesbrecht, who records it from 

 Naples, states that it is probably parasitic on Ophiorjlypha 

 lacertosa = Ophiicra tcxturata of Forbes' ' British Star-fishes,' — 

 a moderately common species in the Firth of Forth. 



Pseudanthessms Sauvagei Canu is another rare species ob- 

 tained during the line-fishing experiments already alluded to. 

 It was discovered in the following manner. During the 

 experiments several specimens of the common Sea Urchin 

 {Echimis esculentus) were among the things brought up on the 

 hooks, and they were treated to a methylated-spirit bath in 

 the same way as the star-fishes, care being taken, of course, to 

 see that the bottle used for each experiment was thoroughly 

 cleaned. After the Sea Urchins had been steeped and washed 

 in the spirit, the sediment was, as usual, examined, with the 

 result that quite a number of this rare Pscudanthessius were 

 obtained — the first time the species had been found in Scottish 

 waters. Several other species of copepoda are known to live 

 on Echinoderms, and if methods similar to those mentioned 

 were employed to catch them, the number of species might be 

 still further increased. 



4. Copepoda associated ivith Annelids. — Zichomolgus hirsutipes 

 T. Scott, a fine species, is another of the trophies captured 

 during the line-fishing experiments carried out in the summer 

 of 1895. Among the various objects brought up on the hooks 

 there was occasionally a long tube formed of blackish mud by 

 a large Annelid — a species of Sabella. These tubes were 

 usually encrusted more or less throughout their entire length 

 with a layer of Alcyonium, but there happened to be one 

 which had its anterior end free from that organism ; and on 

 this one a few white specks were observed scattered over the 

 dark surface of the tube, and big enough to be easily noticed 

 without a lens. Curiosity led me to examine these white 

 objects, when I found them to be copepods belonging to an 



