JATANESE ASTEROIDEA. 61 



the margin, and. is generally oval in outline and covered witli elongate strife 

 running in the direction of the major diameter. 



" The entire body and all its appendages are coTered \vith an investing 

 leathery skin. 



" Size. — Ordinaiy specimens are about 30-40 millims. in diameter, the 

 largest recorded by Sap.s, from Tromso, being 65 millims. 



" Colour. — The colom- is recorded as brown-red ; specimens preseiTed in 

 spirit are either black, gi-eenish, or various shades of drab. 



" Habitat. — Ctenodiscns corniculatus is found in mud or soft clay bottoms 

 at YQYj various de^^ths, being dredged by Saes, at Finmark, in 40-200 

 fathoms depth ; and fm-ther south, at Clnistiansund, in 40-80 fms., by Lisp. 



MÖLLER (LÜTKEN). 



" Fremature form. — The young form of tliis species was described by 

 Müller and Teoschel under the name of Ct. pygmœus. SmaU individuals, 

 of alx)ut half an inch in diameter, are cliaracterized by the flatter test, the 

 comparatively gi*eater prominence of the latero-dorsal spinelets, and the three 

 large, conspicuously-developed spinelets which are present on the terminal 

 plate of the ray. The upper margin of tliis plate, which Hes towards the 

 centi'e of the disk, is fringed with a series of papillae similar to those on 

 the sides of the lateral plates ; and these papillae, as well as the spinelets, 

 appear to be subject to a greater or lesser degree of obhteration (or resorp- 

 tion) dming the progress of the gi'owth of the Starfish ; in fact in old 

 specimens the spinelets become reduced to mere tubercles. 



" According to Lütken, the apical prominence in the centre of the disk 

 is more prominent and characteristically developed in young forms ; but in 

 the sx^ecimens which we have examined (from Novaj'a Zemlya) it would 

 appear to be quite the reverse, for we have been unable to detect any 

 difference, except a proi)ortional diminution in size, from the condition 

 presented by the matm-e animal. The adambulacral plates in these speci- 

 mens bear their pax)ill8e or ' ambulacral spines ' on the fmTow-margin, with 

 one large one placed thmub-Hke beliind them on the aboral side. 



"At the extremity of the ray there are only two of the ambulacral 

 spinelets ; an(J the thumb-like spinelet is larger than either of them, and is 



