20 



TSIDJE. 



Isinae, Dana, Expl. Exped. Zoo})h. 1846, p. 077: Milne-Edw. Brit. 



Foss. Corall. p. 81. 

 Isidea, Ehrenb. C. r. M. p. 133. 

 Isidese, Lamx. Polyp. Flex. p. 458, Corall. p. 229 ; Gray, P. Z. S. 1857, 



p. 283 ; Gray, Ann. $ Mag. Nat. Hist. 1859, iv. p. 442. 



41. ISIS. 



Coral branched, furcate. Axis striated ; branches proceeding from 

 the calcareous articulations. Bark thick, hard, with a few inter- 

 spersed, very irregular and unequal spicula. Polypiferous cells very 

 small, sunken, scattered over the whole surface (Esper, t. 3 a). Base 

 of coral expanded, tuberous. 



Isis, Linn. S. N. p. 1287; Pallas, Zooph. p. 220 ; Solander $ Ellis, p. 101 ; 



Lamk. Syst. A. s. V. p. 378 ; Lamx. Polyp. Flex. p. 468 j Milne-Edw. 



Sf Haime, Corall. i. p. 193 : Gray, P. Z.S. 1857, p. 283 ; Kolliker, Ic. 



Hist. p. 140. 



Cymosaire, Lamk. M6m. Mus. i. p. 467. 

 Hippurium, Oken, Lehrb. 1815, t. 2. 



The bark is very thick, with a few interspersed, very irregular, 

 and unequal spicules, and when dry is rather brittle, but is as per- 

 manent as that of a Gorgonia. It is figured by Solander, Zooph. t. 8. 

 Ellis has justly observed that the sailors generally take it off during 

 the passage to this country to show the black joints. Lamarck, mis- 

 led by this circumstance, never having seen the back, describes it as 

 " caduce en totalite" p. 300 ; he thought that it was gelatinous. 

 It is very apt to fall off if the specimens are kept in a dry place (see 

 form of spicula or bark &e., Quekett, Lectures on Histology, ii. p. 125, 

 f. 64, and Kolliker, 1. c. t. xvi. f. 4, t. xix. f. 1, 2, 3. 



The articulations between the joints generally become obliterated 

 near the base of the coral of the older specimens, either by the con- 

 traction and solidification of the horny part, or by the horny portions 

 becoming covered with a calcareous deposit. 



G. Humphrey, in the Portland Museum (lot 3490), observed a fine 

 specimen of the base or root of the Isis hippuris, which is white, not 

 jointed, with the black woody parts, as in the stem and branched 

 part that was next the body, quite flat. He adds it is not figured 

 by any author, and is extremely rare. Lamarck, not aware of this 

 fact, established for the root of a specimen which had the joint so 

 obliterated the genus Cymosaire ; but he soon discovered his error 

 and corrected it, with his usual honesty and straightforwardness. 



" Le genre Cymosaire (Mem. du Mus. vol. i. p. 467) doit etrc 

 supprime. Je le fondoit par erreur sur la vue d'une portion d'axe a nu 

 d'une Isis, dont la base offre un empalement rameux et en cyme 

 ombelliforme." Lamk. A. s. V. ii. p. 393 ; see Seba, iii. 1. 105. f. 3. 



Professor Steenstrup has divided the genus into several species, 

 according to the form and length of the stony joints. I have not 

 been able to decide if they are species or only accidental varieties. 

 The coral is very variable from the same locality. 



/. hippuris. The stony joints elongate, cylindrical, or narrow in 

 the middle, two or three times as long as thick. Amboina. 



