40 HOLOTHURIOIDEA. 



Attains a large size. Podia not confined to ambulacra. Body a 

 more or less swollen sac ; podia retractile, sometimes in four rows 

 in ambulacra near middle of body ; not many interambulacra podia ; 

 the arrangement of the podia varies a good deal with age. Skin 

 soft and smooth. 



Deposits very variable both in form and in the extent to which 

 they are developed ; often almost or quite absent in large examples. 



Colour ordinarily purplish or dark slate, the podia lighter, as is 

 sometimes the ventral surface. Occasionally the whole creature is 

 of a much lighter hue. 



May be as much as a foot long, and four or five inches wide, 

 capable of extension to twice this length or more. 



Distribution. Circurnpolar, extending southwards to Britain, 

 Florida Beef, and California. 3-220 fms. 



a. Off Faeroe Islands, 70 fms. R. K. Burt, Esq. 



b. Orkneys. 



c-k. West coast of Scotland. John Murray, Esq. 



l-m. Montrose. W. Duncan, Esq. 



n. Plymouth. 



7. Cucumaria fucicola. 



Holothuria fucicola, Forbes fy Goochir, Athencrum, no. 618 (1839), 

 p. 647 ; Norman, Rep. Brit. Assoc. 1868 (1869), p. 316 ; Ljungman, 

 (Efv. Vet.-Ak. Forh. 1879, no. 9, p. 127. 



I have not seen this species, which most authors have united 

 with G. frondosa. Mr. Norman, however, noted the following 

 points of difference. He says :— 



" Cucumaria fucicola (Forbes & Goodsir). 



" The type-specimens were found not uncommonly ' in Bressay 

 Sound, Shetland, in 7 fathoms water, adhering to the stems of 

 Laminarise,' and thus in the same locality with O. frondosa. Von 

 Diiben and Koren (CEfversigt af Skandinav. Echinod. p. 294) 

 referred this species to the young of G. frondosa, and their 

 synonymy has been copied by all subsequent writers without 

 inquiry. But the young of C. frondosa is like the adult, in that 

 ' corpus, collum et pedum latera teguntur granulis calcareis, irregu- 

 laribus, difformibus, nunquam perforatis, which is not the case with 

 C. fucicola. 



" Specimens of this species, procured by myself in the typical 

 locality, have the skin supplied with calcareous plates, which are 

 very irregular in form and size, but when fully developed are nearly 

 round, rather longer, however, than broad, and perforated with as 

 many as 30-40 holes. The sides of the feet are likewise furnished 

 with the irregular-shaped, elongated, perforated plates common in 

 this position in the different species of the genus ; but these feet- 

 spicules I have also observed sparingly present in the young of C. 

 frondosa, though in the passage above quoted Diiben and Koren 

 deny their existence." 



