120 ECHINODERMATA. 



COMATULA BARBATA. — Plate XXX. 



The animal described in this paragraph is nearly allied to the Star- 

 fish, especially to those of that genus last named, the Ophiura. Never- 

 theless some parts of its history being unintelligible as such, and its pe- 

 culiarities being so strong and decided, a distinct genus has been instituted 

 to receive it. 



Individually, the Comatula, which bears a general resemblance to 

 the Star-fish, consists of a small circular, flattish disc, scarcely two lines in 

 diameter, whence issue ten disproportionately long pinnate rays, expand- 

 ing about five inches between the opposite extended extremities. 



The whole surface is from tile-red to crimson colour : — Plate XXX. 



fig-1- 



One surface of the disc is provided with ten or twelve slender or- 

 gans, each terminated by a claw, which, from their action and use, may 

 1)6 described as claspers. They serve to affix the animal to foreign sub- 

 stances, as seen fig. 2, where they are rei^reseuted as adhering to an 

 Ascidia. These organs are variegated red and white ; but their figure and 

 appearance are best discovered by the microscope, fig. 3. The form of 

 the opposite surface tends to that of a hemispherical segment, which in 

 one specimen was obscurely partitioned into triangular compartments. 

 Also there is an orifice, probably the mouth, in the centre. Farthei-, in 

 another compartment, is a nipple, with an orifice, said to be the vent, 

 projecting in variable shape and aspect, fig. 4. It does not appear in 

 every specimen. 



A double row of minute suckers, visible with microscopic aid, 

 clothes the under surface of the ray, and that of the claspers. 



The Comatula remains during whole days adhering pertinaciously to 

 the same spot. In swimming, it is with a singular motion — somewhat 

 undulatory of the rays, on which occasion the claspers are always below. 



Extraordinary mutilation is incident to this creature. It is aUke 

 liable, as the Ophiura, to fall to pieces. Indeed, this is the way wherein 

 all seem to perish. Part after part drops ofi", until only the naked disc 

 remains, the water being slightly tinged by the decay. 



