COLURID.E. 4!) 



MYTILIA PCECILOPS, Gosse (171), (PI. XXXI. fig. 51). 



[SP. CH. Lorica perg amentaceous, very flexible, constantly thrown into irregular 

 folds, whence the outline is very variable ; the face,, in particular, is capable of great 

 protrusion in wide plicate membranes ; prevalent figure, foot, and toes, much as in 

 M. teresa. 



Though this has many features in common with tavina and teresa, particularly 

 the foot and toes, it has important peculiarities. The dorsal outline is like that of the 

 latter, the lateral that of the former ; but both more rough and uncouth. The skin 

 thrown irregularly into coarse rude folds, occurring at intervals at every part, precludes 

 any fixed form, so that the figure accurately copied has become in a few minutes, though 

 gradually, flagrantly incorrect. The front is large and broadly truncate, capable of 

 pushing out, from its lower part, great membranous sacs and folds, which slowly change 

 every moment, and the use of which is inexplicable. These expansions do not appear 

 to be ciliated. The mastax and trophi are as in its congeners ; there is an ample brain, 

 which carries a cervical red eye. The whole back is ridged tectiform, not keeled. 



I have observed numerous examples in sea-water from the Invergowrie tide-pools. 

 They have all been remarkably heavy and sluggish in manners, little given to locomo- 

 tion, wholly lacking the sprightly vivacity of the kindred species, and unusually 

 intolerant of captivity. The abdominal viscera are generally of a rich orange-brown 

 hue, and the whole tissues are more or less suffused with the same colour. 



Length (lorica), ^-^ inch. Habitat. Invergowrie, tide-pools. P.H.G.] 



MYTILIA PRODUCTA, Gosse (171), (PI. XXXI. fig. 53). 



[SP. CH. Skin flexible, plicate ; body slender, very extensile ; eye single, frontal ; 

 foot and toes nearly as in M. teresa. 



The lorica, flexible in If. pmcilops, is perhaps even more so in this species, and 

 recognisable only at the posterior extremity, where each lateral plate can be traced, as, 

 with a rounded end, it curves under the trunk, to approach its fellow-plate, leaving a 

 narrow ventral cleft. The face is quite truncate, slightly oblique, not abnormally de- 

 veloped. When gliding rapidly along a seaweed, the animal is very worm-like, the body 

 and the foot, about equal in length, forming two successive cylinders, the latter half as 

 thick as the former. But both, especially the foot, are capable of sudden elongation at 

 will. Thus the creature has a facies which distinguishes it from either of its congeners . 

 Perhaps it comes nearest to teresa. The toes are even broader proportionally ; together 

 much exceeding the width of the foot whence they issue. The eye is conspicuous, nearly 

 frontal, but changes its position with the brain. The whole animal is colourless, but 

 very full of folds and corrugations. Very long mucous glands proceed from the toes 

 through the whole of the foot. 



The species first occurred to my observation on May 7, 1887, on very fine seaweeds 

 (Ceramium), which I gathered in the deep cup-like pool in limestone rock at Oddicombe 

 Point. I met with about half-a-dozen examples. 



Length, y^ inch. Habitat. Marine, Devonshire. P.H.G.] 



MYTILIA TBEESA, Gosse (169), (PI. XXXI. fig. 52). 



[SP. CH. Body truly oval ; toes together wider than foot ; each toe large, long, 

 ovate, abruptly produced to a long, slender, acute point. 



This very pleasing species I have found in some abundance, in water dipped for me 

 out of tide-pools in various parts of Torbay by my little granddaughter, with whose name 

 I honour it. It has a very distinct red eye in the occiput. The large bulbous toes are 

 peculiar. It is a sprightly creature, playing actively among confervoid algae, often 

 pivoting on its toes, like a Cathypna, jerking and bowing ; it is less locomotive than 

 M. Tavina. 



Length, ^ inch. Habitat. Marine, Torbay. P.H.G.] 



