156 CLASS IV. 
Cidaris Kunin, Cidarites Lam. (Cidaris, Diadema, Astropyga 
Gray, Aaass.) Ambulacra parallel. Tubercles sustaining the 
spines not perforate, often remarkable for their size. 
Sp. Cidaris verticillata, Gur. Iconogr. Zooph. Pl. 3, fig. 1; in the Indian 
Sea, on the coasts of Timor, &c. Of this genus many fossil species also 
are known. 
Family IV. Holothuridea. Body free, mostly cylindrical, 
covered with a coriaceous skin, furnished with calcareous particles 
scattered, reticulate. Mouth surrounded by retractile tentacles. 
Anus terminal, opposite to the mouth (Genus Holothuria L. exclu- 
sive of several species). 
Comp. on this family : 
G. J. JAncer De Holothuriis, Dissertatio inaug. Turici, 1833, 4to. 
cum tab. J. F. Branpr Prodromus descriptionis animalium ab 
H. Merrensio in orbis terrarum circumnavigatione observatorum. 
Fasc. 1. Petropoli, 1835, 4to. pp. 42—62, GruBe Actinien, Hchino- 
dermen und Wiirmer des Adriatischen und Mitilemeers, Konigsb. 
1840, 4to. pp. 33—42. There are many figures of European 
Holothurice in the Zoologia danica and of foreign species in Lesson 
Centurie Zoologique, Paris 1830, 8vo. 
We have spoken above (p. 140) of the calcareous ring which may 
be considered as a vestige of a skeleton, and which serves for the 
attachment of the longitudinal muscles. The pieces of which this 
ring consists are toothed above, but they do not discharge the office 
of teeth, the food, as far as it undergoes separation and mastication 
previous to deglutition, being thus effected by the callous skin 
surrounding the mouth alone. Holothwrie feed upon conchifera and 
other marine animals ; TIEDEMANN frequently found shells entire and 
uninjured in the intestinal canal of Holothuria tubulosa, so that the 
molluses appeared to have been dissolved in the shell and digested. 
The bits of shell and the other matters unfit for use and undigested 
are rejected from the cloaca with the water in expiration. We 
have indicated above the chief particulars respecting the internal 
structure. 
See, besides, TrEDEMANN 1.1., also the beautiful engraving from a prepara- 
tion by Hunter in Catalogue of the Physiolog. Series of Compar. Anat. 
contained in the Museum of the Royal College of Surgeons, Vol. 1. London, 
1833, Pl. 111. pp. 250—254. 
The numerous species of this family are separated according 
to the form of the Tentacles (LAMARCK, GRUBE), the position of the 
