The British Star-Fishes. 253 



mities, but by successive deposits of calcareous matter at the 

 base of the spine, the hooks are constantly pushed forwards 

 and finally obliterated. They are, however, occasionally ob- 

 served in mature specimens, and in cases where a rejected 

 limb is in process of reconstruction. Fig. c in the woodcut is 

 copied from Mr. Hodge's illustration of the c ' hooks" of young 

 Ophiocoma rosula, and Fig. d represents one of the spines of 

 an adult specimen. The common " Cross-fishes" (Uraster) of 

 our coast have a reticulated surface, set with lines of short, but 

 sharp spines : these differ in length and strength according to 

 species. In Uraster glacialis they are very strong, and arranged 

 in well marked ridges. In this genus are constantly noticed 

 the peculiar appendages termed Pedicellarice, of which we shall 

 have more to say further on. Cribella has a non-reticulated 

 surface, but in lieu of the network and spines is covered with 

 small tubercles mostly irregularly arranged. About these 

 there is not much to interest the microscopist. 



Among the largest and handsomest of British star-fishes is 

 Goniaster equestris, the Sea-pincushion, as it is called by our 

 northern fishermen. The appellation is not inapt, for the large 

 fleshy mass of the animal is covered thickly with round bosses 

 or tubercles of the size of a large pin's head. Each of these is 

 encircled at the base by a series of smaller tubercles, generally 

 from twenty to thirty in number. Interspersed among the 

 tubercles over the whole upper surface, but still more numerously 

 beneath, are certain pincer-like organs, composed each of two 

 flattened lips or valves, which fit together accurately, and which 

 during the life of the animal may be seen in constant motion, 

 opening and shutting, so at least say the fishermen. I have 

 never myself seen the creature alive. I do not, however, doubt 

 the fact. Dr. Johnston states that the radiating circles of 

 spines of Luidia (described further on) have the power of volun- 

 tarily opening and closing in a similar manner ; and he also 

 noticed the same phenomenon in the present species. These 

 pincers are likewise surrounded by circles of small tubercles. 

 The pentangular disk and rays are bordered by a double row 

 of flattened plates, each of which bears three or four large 

 tubercles, and is encircled by a series of minute ones in the 

 same way as the simple tubercle of the disk. The elaborate 

 ornamentation and great size of this species make it a very 

 desirable addition to the cabinet. It is often brought in in 

 considerable numbers by the trawlers on our north-eastern 

 coast, and specimens not unfrequently measure ten or eleven 

 inches in diameter. 



A striking contrast to this large and fleshy species is Pal- 

 mvpes membranaceus, the " Bird's -foot Sea-star," which is 

 almost as thin as parchment, and might, as Professor Forbes 



