Sea-slugs 



287 



side from under the edge of the mantle extend many 

 hranclicd cerata, much like curled and crisped fronds 

 of one of the smaller seaweeds. The liver does not 

 extend into the cerata in this genus. The head 

 is sheltered by a lobed and toothed veil. The 

 tentacles issue from large sheaths with spreading 

 mouths, and the rhinophores take the form of a 

 circlet of fern-like plumes. This slug is never found 

 away from the Deadman's Fingers (Alcyoniuvi 

 digitatitm) whose closed pol^^ps are mimicked by 

 the tubercles on the Triton's back. The colour 

 variation in this and some other species appears to 

 have relation to their food ; for T. homheryi has 

 been experimentally kept without its favourite food, 

 when it lost all its colour and became transparent. 

 There are three other species, of which the best 

 known is the Common Triton (T. pleheia), a much 

 smaller species, found in similar situations to the 

 last named. It is just as variable in colour — -just as 

 the Alcyonium is variable, and in the same tints — 

 and its rhinophores equally mimic the half-extended 

 croAvn of tentacles of the polyp. But jdeheia is little 

 more than 1 inch in length, and its head veil, though 

 divided into seven or eight finger-like appendages, 

 is not lobed. 



The Gulf -weed Slug (Scyl- 

 Icea loelagica) is a quaint 

 little creature less than 1 inch 

 long, with rhinophores in long 

 sheaths, and two pairs of 

 spreading cerata along the 



sides. It is found only on floating seaweeds, and 

 was at one time thought peculiar to the Gulf- 

 19 



Gulf-weed Slug 



