A MONOGRAPH OF THE EXISTING CRINOIDS 263 



He gave a table showing the variations in 1 1 specimens from Ceylon (see p. 338). He 

 pointed out that in these the number of the cirrus segments is most constant. • These 

 are always broader than long, as given by Carpenter for carinata; but the relation of 

 the breadth to the length is not always the same, as is seen by a comparison between 

 the length of the cirri and the number of the component segments. Carpenter gave 

 XX-XXX cirri with 20-30 segments. He pointed out that Carpenter said that some 

 relatively yoimg individuals were taken at Bahia by the Challenger, and that "They 

 differ from the mature individuals in the greater length of the arm- and cirrus-joints." 

 In Reichensperger's opinion Carpenter was entirely correct in not separating the 

 forms he included under carinata, for these appear to be inextricably united with each 

 other. Transitional forms, which are much more common than the extreme or 

 typical forms, prove that Tropiometra carinata is to be considered, as was done by 

 Coimt Pourtalds and Carpenter, as a single specific stock whose enormous geo- 

 graphical range with diversified living conditions leads to the appearance of varieties 

 or racial stocks which in no way lose the specific characteristics, and at the most 

 vary one from another only in the slightest degree. Reichensperger concluded that 

 an attempt to establish discontinuous specific divisions among the forms of carinata 

 would lead not to clarifying, but to obscuring the mutual relationships within this 

 interesting group. 



In 1915 Dr. Hubert Lyman Clark recognized encrinus and indica as valid forms, 

 recording both from Ceylon. In 1916 Dr. Clark compared in minute detail long 

 series of specimens from Tobago, British West Indies, from Brazil, and from Mauritius 

 and Zanzibar, coming to the conclusion that they all represent the same specific type. 

 This conclusion was in the same year accepted by Mortensen, who had been with 

 Dr. Clark at Tobago. Mortensen did not himself look into the matter, but simplj'^, 

 and quite properly, accepted his colleague's conclusions. 



In 1932 I pubhshed a detailed description of Tropiometra encrinus based upon 

 five specimens from near Mandapam in the Madras Presidency of India. I also was 

 able to study other specimens from the eastern coast of India. The specimens from 

 Mandapam were very large, some of them with the arms about 180 mm. in length. 

 Furthermore, the brachial carination was much reduced, becoming obscure after the 

 proximal fourth of the arms and completely disappearing in the outer half. At first 

 glance these specimens look more like examples of T. afi-a or an allied form than like 

 examples of a form allied to carinata. The other specimens from the eastern coast of 

 India are in general agreement with these, though not so hirge. The brachial cari- 

 nation is much reduced, usually disappearing in the outer half of the arms, though 

 very faint suggestions of it may remain. 



In 1933 Dr. Torsten Gisl6n made a careful comparison between 18 specimens 

 from St. Helena and others from Tobago, Portuguese East Africa, and Zanzibar. 

 These were compared with specimens in the Copenhagen Museum identified as 

 Tropiometra encrinus by the author. His conclusions were that en<;rinus seemed to 

 be a valid form, but that picta from the western Atlantic must be regarded as a syno- 

 nym of the African carinata. 



On reexamining the question of the interrelationsliips of these forms I find myself 

 in agreement with my colleagues Drs. Clark and Gisl^n. There are no tangible 

 differences between specimens from the southeastern African region (typical carinata) 



