3S2 



ECHINODERMS OF THE BRITISH ISLES 



tliereby gets an almost shaggy appearance ; on the contrary the 

 tube-feet are scarcer on the anterior end of the trivium than 

 in intestinalis. Spire of the tables ending in four simple points 

 (Fig. 224, 4-5) ; tables of the tube-feet reduced, smaller than 

 those of the skin. Colour in life light grey, with a tint of violet. 

 Grows to about the same size as intestinalis. 



It appears that this species does not cover itself with foreign 

 bodies, the skin of preserved specimens being clean and white. 

 It appears to be unisexual. 



In British seas this species has been found off S.W. Ireland, 

 in ca. 990-1765 m. (*' Helga "). It is elsewhere known from the 

 Bay of Biscay to the Azores, the Canaries, and the Mediterranean, 

 and also from the West Indies. Bathy metrical distribution ca. 

 280-2520 m. 



3. Mesothuria lactea (Theel). 

 (Fig. 226.) 



(Syn. Holothuria lactea Theel ; Zygo- 

 thuria lactea (Theel) Perrier ; 

 (?) Holothuria aspera BeU.^) 



Body rather flattened, broader in 

 the posterior end. Tentacles 15-20. A 

 single series of rather distant, conical 

 tube-feet in the ventro-lateral ambu- 

 lacra, none in the mid- ventral radius. 

 lit 'Mr -II Dorsal papillae few or wholly wanting. 



im Hf I Deposits (Fig. 227) of the 3-radiate 



\*^Ku .jfiJi?*/ type, the spire ending in 3 smooth 



points, the disk wdth six regular peri- 

 pheral holes. In the basal part of the 

 tube-feet supporting rods occur ; in 

 the outer part more or less reduced 

 tables. Colour in life whitish or grey. 

 Grows to a size of ca. 15 cm. Appar- 

 ently unisexual. 

 A form with the sj)ire of the tables ending in a simple point, 

 and with usuall}^ a number of small holes outside the usual 



^ It seems very probable that the Holothuria lactea of Bell is really 

 identical with this species, the star - shaped spicules of that species 

 {Catalogue Brit. Ech., p. 50) being, as pointed out by Massy, " very like the 

 beautiful wide-meshed disks of M. lactea, if the deposits examined had the 

 outer rings of the tables broken away or not developed ". Such spicules 

 were actually found by Massy in portions of the perisome of one specimen 

 of M. lactea. 



Fig. 226. — Mesothuria lactea ; 

 ventral side. Somewhat 

 reduced. (After Herouard, 

 " Monaco'", xxi.) 



