HOLOTHURIOIDEA 393 



and on the adjacent Atlantic coasts ; three of these occur as far 

 north as the French coasts, viz. Holoth. Sanctori Delle Chiaje 

 (Syn. H. farcimen Selenka), H. tubidosa Gmehn, and H. Polii 

 D. Chiaje. There may perhaps be a sHght possibiUty of finding 

 these species also at the British south coasts, so that it may be 

 desirable to give a key by which they may be distinguished. 

 A detailed description of these species is given in Koehler's 

 Echinodermes, Faiine de France.^ 



Key to the species of Holothuria known from or possibly 

 occurring in the British seas. 



1. Deposits very scarce and rudiment arj^ ; no tables 



1. H. Forshali D. Ch. 

 Deposits numerous and well developed ; tables and buttons 2 



2. Disk of tables with smooth edge . . H. Sanctori D. Ch. 

 Disk of tables with serrate edge ..... 3 



3. Buttons with smooth surface . . . . H. Polii D. Ch. 

 Buttons with rough surface . . . H. tiibulosa Gmel. 



1. Holothuria Forskali Delle Chiaje.^ 



C' The Nigger " or " Cotton- Spinner ".) (Fig. 234.) 



(Syn. Holothuria nigra Peach, Gray (Kinahan), Bell ; H. catanensis 

 Grube ; Stichopus Selenkce Barrois.) 



Ventral side flattened, with numerous tube-feet, forming three 

 or four longitudinal series, the middle one being often divided 

 in two by a naked median space. Dorsal side with conical 

 paj)ill9e. Skin thick, soft. Cuvierian organs present. Deposits 

 scarce and small, usually with 4 holes, sometimes with small 

 tubercles (Fig. 235) ; in the tube-feet and papillae elongate, 

 irregularly branched rods, in the tentacles curved rods. Colour 

 in life usually black on the dorsal side, the ventral side lighter, 

 brownish or yellowish. The dorsal papillae white at the tip, or 

 they are (according to Norman) white with a black tip. Tentacles 

 yellow. The general colour may also be, on the whole, lighter ; 



^ Sluiter (" Holothiirien Sammlung d. Mus. Amsterdam ", Bijdr. tot 

 de dierk, xvii., 1895) records Holothuria glaherrima Selenka from the Nortli 

 Sea (found in the stomach of a cod), and Holoth. stellati Marenzeller from 

 the coast of England. The former species being elsewhere known only 

 from the West Indian seas, the latter only from the Mediterranean, it is 

 rather safe to say that there must be some mistake here, duo either to 

 incorrect labelling or to erroneous identification. There is no reason for 

 further mentioning these species in the present work. As for H. stellati, 

 which may possibly occur also outside the Mediterranean, a description 

 will be found in Koehler's Echinodermes, Faune de France. 



^ The name is also written Forskahli or Forsk&lii. 



