196 LECTURE X. 



of light, at least, on wliich its peculiar colour depends. The terminal 

 pigment-speck in most star-fishes is defended by a circle of moveable 

 spines, which on the visual hypothesis of the speck have been called 

 " eyelids." But, without regarding the subjoined facetious descrip- 

 tion by a witty contemporary, either " as giving additional weight to 

 their asserted claims to be regarded as true visual organs,"* or as 

 meriting the grave refutation with which it has been honoured by a 

 worthy matter-of-fact German anatomist +, we quote it simply as 

 indicative of the prevalent notion amongst sound naturalists of the 

 function of these problematical parts. Prof. E. Forbes, often baffled 

 by the suicidal powers of the star-fishes, liad taken special precau- 

 tions to obviate the consequences in regard to a rare " brittle-star ; " 

 and had provided a bucket of fresh water to receive and kill instan- 

 taneously any specimen that might be brought up by the dredge. 

 "As I expected, a Luidia came up — a most gorgeous specimen. As 

 it does not generally break up before it is raised above the surface of 

 the sea, cautiously and anxiously I sank my bucket to a level with 

 the dredge's mouth, and proceeded, in the most gentle manner, to 

 introduce Luidia to the purer element. Whether the cold element 

 was too much for him, or the sight of the bucket too terrific, I know 

 not, but in a moment he proceeded to dissolve his corporation, and at 

 every mesh of the dredge his fragments were seen escaping. In 

 despair I grasped at the largest, and brought up the extremity of an 

 arm, with its terminating eye, the spinous eyelid of which opened and 

 closed with something exceedingly like a wink of derision." 



The mouth in the star-fishes is situated at the middle of the under 

 surface of the body : it is edentulous, and leads by a short wide 

 gullet into a large stomach {fig. 93, a), which, in the StelleridcB, 

 sends off a pair of sacculated ccecal appendages {bb) into each of the 

 rays, but is without intestine or anus in Ast. aurantiaca {Astero- 

 pecten). The small terminal pouches of these appendages appear to 

 secrete a substance subservient to chylification : two or more small 

 glandular sacs (cc) of a yellowish colour open into the bottom of the 

 stomach, and have been regarded as a rudimental form of liver. In 

 Asteracanthion, Asterogoiiiwn and Solaster, there is a short intestine 

 with an anal opening, opposite to the mouth ; and in these there are 

 inter-radial caeca, which in Asteracanthion rubens contain a brownish 

 fluid, in which uric acid has been detected. Each long sacculated 



* CLXV. p. 253. 



•j- " Die von Forbes (History of Star-fishes, p. 139.) mitgetheilte Erzalilung, wie 

 Luidia fragilissima cliireh freiwilliges Abtrennen der Arnie, mit spottisch blinzelnden 

 Augen ihren Verfolger anblickend, sich der Gefangenscliaft zu entziehen -Riisste, ist 

 recht anziehend zu lesen, kann aber natiirlich nichts iiber das Dasein von Augen 

 bei den Seesternen entschieden." XXIV. p. 88. 



