History of British animals - University of Guam Marine Laboratory

Cidaris. RADIATA. ANOCYSTI. 477the sockets of the teeth. According to this author, the water entersthe perforated suckers, passes along the five tubes, and escapes at themouth. Future observation, however, will probably assign an oppositedirection to the current, and the perforated tubes on the oral discas the orifices at which the water enters.The organs of reproductionappear to be limited to five ovaria, intimately connected, and openingby five oviducts, in the perforations of the five plates of the pelvis.When in season, the roe fills a great part of the cavity of the shell. Itiseaten when boiled, and has a flavour not unlike a lobster.Gen. I. CIDARIS.— Tubercles and spines connected by acentral ligament. The avenues of pores are parallel andclosely placed, rendering the smaller compartments narrow,tortuous, and fitonly for supporting small spines. Theplates of the larger compartments have an elevated tuberclein the middle, with a groove round the base, surroundedwith a broad smooth space, which is inclosed on themargin of the plate, with a border of small tubercles, destituteof a pitin the summit. On each central tuberclethere is placed a large spine, connected by the central ligamentand investing integument. M. Lamarck (Hist.Vert. iii. 53.) considers this central ligament as a muscleBut it hasissuing from the interior, for moving the spine.no communication with the interior of the shell.He likewisesupposes that the tubular suckers can be withdrawninto the shell by the animal. But the division of the canalat the base, for the passage ofeach branch through a differentpore,renders this impossible.Round the base ofthese large spines,smaller ones are placed, on the ring oftubercles, which surround them like a sheath.Each avenueconsists only of a double row of pores,in pairs, correspondingwith a single row of tubular suckers.1. C. papillata.— Primary spines nearly cylindrical, with numerousrough longitudinal ridges.C. p. major, Leske apud Klein, Ech. p. 125. tab. vii. A. and xxxix.—2. Echinus Cidaris ? var. a. Sower. Br. Mus. tab. xliv—Found in deepwater, Zetland, where it is called the Piper.The body of the shell is about two inches in diameter, and depressed atboth ends. The longest primary spines are about four inches in length. Theshortest near the mouth do not exceed half an inch. These last are spatulateas well as the small ones on the oral plate. The plates of the division be-