NO. 2 DEICHMANN: HOLOTHURIOIDEA; PARTII, ASPIDOCHIROTA 277 



ment and much of what is presented here is more or less foreshadowed in 

 the key which W. K. Fisher made for the Hawaiian holothurians in 

 1907. 



Affinities to Other Regions 



The aspidochirote shallow water forms may be grouped roughly as 

 follows : Two species are almost circumtropical, Brandtothuria arenicola 

 and B. impatiens, while six appear to be offshoots from the west Pacific 

 and from their sparse occurrence may be considered more or less casual 

 visitors in the Panamic region: Ludwigothuria atra, Mertensiothuria 

 fuscocinerea, Brandtothuria gyrifer, Semperothuria imitans, Mertensio- 

 thuria leucospilota, and Lessonothuria pardalis. Four species are closely 

 related to West Indian forms and apparently do not occur outside the 

 Panamic region: Isostichopus fuscus, Ludwigothuria kefersteini^ Sem- 

 perothuria languens, and Selenkothuria lubrica, with the corresponding 

 forms in the West Indies: Isostichopus badionotus, Ludwigothuria 

 grisea, Semperothuria surinamensis, and Selenkothuria glaberrima. 



Another group is widespread in the Indo-West Pacific region and 

 has more or less closely related counterparts in the West Indies : Micro- 

 thele difficilis, Jaegerothuria inhabilis, Theelothuria paraprinceps, 

 Fossothuria rigida, and Vaneyothuria zacae, with the corresponding 

 West Indian forms Microthele parvula, Jaegerothuria occidentalism 

 Theelothuria princeps, Fossothuria cubana, and Vaneyothuria lentigi- 

 nosa. Theelothuria paraprinceps in all probability will be found to be 

 identical with some older species from the East Indies, while Vaney- 

 othuria zacae may be withdrawn as a synonym of some such form as 

 V. integra or V. neozelanica. 



Apparently endemic to the Panamic region are Labidodemas ameri- 

 canum, Irenothuria maccullochi, Selenkothuria portovallartensis, and 

 S. theeli, to which it seems proper to add Mertensiothuria platei, from 

 Juan Fernandez, as it may possibly extend into the southernmost part 

 of the Panamic region and is not known from outside the American 

 waters. 



Aside from Isostichopus, the total absence of such large lagoon forms 

 as the members of the genera Actinopyga, Bohadschia, Astichopus, etc., 

 is noteworthy. 



Compared with Hawaii and the West Indies, using Fisher's and 

 Deichmann's papers, the supposedly barren shores of the Panamic region 

 have more aspidochirote forms than either. About one third of the fauna 



