A MONOGRAPH OF THE EXISTING CRINOIDS 343 



Tropiomelra audouini A. H. CLARK, Proc. U. S. Nat. Mus., vol. 43, 1912, p. 384 (identity), p. 401 

 (detailed description; Eig Tor, Gulf of Suez; Ras-el-Millan, Gulf of Suez; Aden; comparisons 

 with other species) ; Beitrage zur Kenntnis der Meeresfauna Westafrikas, Echinod. II, Crinoidea, 

 1914, p. 313 (range; Red Sea). HARTMBYBR, Mitt. Zool. Mas. Berlin, vol. 8, No. 2, 1916, 

 p. 236 (Erg [not Eig] Tor; No. 5602 [type]). A. H. CLARK, Unstalked crinoids of the Siboga- 

 Exped., 1918, p. 131 (in key; range); Journ. Linn. Soc. (Zool.), vol. 36, No. 249, April 1929, 

 p. 646 (Hurghada; notes); Rec. Indian Mus., vol. 34, pt. 4, 1932, p. 564 (range); John Murray 

 Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 1936, p. 87 (listed), p. 92 (Mabahiss station 53; 

 notes; range), pp. 101, 104, 105. MOHTENSEN, Kongel. Danske Vid. Selsk. Skrifter, nat. math., 

 Afd. 9 Raekke, vol. 7, No. 1, 1937, p. 7 (listed), p. 61 (description of larvae), pi. 14, figs. 1, 2. 



Diagnostic features. The brachial carination, which is only moderately developed, 

 extends to the arm tips; the cirri are XVI-XXIII, 16-18, 13 mm. long; the arms are 

 50-80 mm. long; the proximal pinnules are stiff and spine-tipped. 



Notes. In the specimen from Ras-el-Millan the cirri are XXIII, 16-17, 13 mm. 

 long. Many of the cirri are small, from 9 mm. with 14 segments upward. These all 

 appear to be juvenile cirri which will be lost before maturity is reached. The arms 

 are about 50 mm. long. The lower pinnules have sharp tips. 



In the specimen from Erg Tor the centrodorsal is thick discoidal with a single 

 marginal row of cirrus sockets. 



The cirri are XVI, the only one remaining having 18 segments and being 13 mm. 

 long. The outer cirrus segments are about half again as broad as long. 



The arms are about 80 mm. long. The carination on the brachials is moder- 

 ately developed. 



The lower pinnules are very stiff, especially P 2 , P 3 , and P 4 . PI is 7 mm. long with 

 16 segments. P 2 is 7 mm. long with 14 segments, and is stouter basally than Pj. P 3 

 is 6.5 mm. long with 16 segments. P 4 is 6 mm. long with 16 segments. P 2 , P 3 , and P 4 

 sometimes have spinelike tips resembling those of the proximal pinnules of the species 

 of Stephanometra, and are very stiff. PI is also more or less stiffened. P 6 is 6.5 mm. 

 long with 20 segments, slender, delicate, and distally flagellate, not stiffened like the 

 pinnules preceding. P 8 resembles P 6 . The distal pinnules are very slender. 



The specimen from Aden is rather small. 



The brachial carination in this species differs from that in T. indica in being 

 broader, more rounded, and less sharp, and it is also fringed with coarser spines on its 

 distal border. 



Carpenter said that in the. few specimens that he had seen from Muscat and from 

 the Red Sea the indication of the middorsal line on the lower brachials from the second 

 onward and the synarthrial tubercles are considerably less distinct than in "those from 

 the Indian Ocean, Brazil, or the Caribbean Sea" that is, than in the other forms; 

 while in specimens from the Red Sea the terminal portions of the arms, as in the 

 African variety (carinata) have stiffer pinnules and a less feathery appearance than is 

 the case in Brazilian specimens. 



Larvae. Dr. Mortensen wrote: 



This comatulid, which occurs in good numbers on the reefs close to the station [Marine Biological 

 Station of the University of Egypt, at Ghardaqa on the Red Sea coast, a little south of the Gulf of 

 Suez], mainly on the under side of old loose coral blocks, was found ripe by the end of April. Some 

 specimens were put into a large dish on the 18th and the next morning a good number of eggs were 

 found lying on the bottom of the dish. The egg membrane is spiny as in Tropiometra carinata. 

 About 24 hours old the embryos were partly free swimming, and on the next day there were some 



