this latter region is even more reduced. In light of the fact 

 that molids have their closest anatomical affinity with 

 triodontids and that diodontids and molids are 

 anatomically extremely different, there is every reason to 

 believe that the reduction in the bony structure in the 

 caudal region of diodontids has taken place indepen- 

 dently of that in molids, and that it in no way indicates 



that the diodontid caudal peduncle was a precursor to 

 the abortion of the rear end of the body in molids. The 

 diodontid caudal peduncle has probably become reduced 

 from that found in most of the ancestral tetraodontoids 

 concomitant with the development of the huge spines 

 that guard the body in diodontids as a slow swimming 

 highly defensive mode of life was evolved. 



Material Examined 



Length in millimeters is always standard length, and, 

 unless otherwise stated, the Recent specimens listed 

 below are cleared and alizarin stained preparations. In- 

 stitutional abbreviations are as follows: ANSP, 

 Academy of Natural Sciences of Philadelphia; BMNH, 

 British Museum (Natural History), London; GVF, 

 George Vanderbilt Foundation, fishes now at the Cali- 

 fornia Academy of Sciences, San Francisco; JLBSII, 

 J.L.B. Smith Institute of Ichthyology, Grahamstown, 

 South Africa; SU, Stanford University, Calif, (now at the 

 California Academy of Sciences, San Francisco); TABL, 

 Tropical Atlantic Biological Laboratory, U.S. Bureau of 

 Commerical Fisheries (now National Marine Fisheries 

 Ser\'ice), Miami, Fla.; USNM, United States National 

 Museum (National Museum of Natural History), Wash- 

 ington, D.C.; WAM, Western Australian Museum, 

 Perth. 



Recent Species 

 PLECTOGNATHI 

 Triacanthodidae 



Atrophacanthus japonicus (Kamohara): ANSP 102138, 

 2, 9.1-10.4 mm, Celebes; ANSP 102139, 5, 35.6-43.1 

 mm, Celebes; BMNH 1960. 5.4.1, 1, 34.7 mm, Celebes. 



Halimochirurgus alcocki Weber: USNM 93474, 1, 124 

 mm, Philippines. 



Halimochirurgus centriscoides Alcock: ANSP 100828, 

 2, 99.2-113 mm, Bay of Bengal. 



Hollardia hoUardi Poey: ANSP 103303, 1, 84.7 mm, 

 Puerto Rico; ANSP 100867, 2, 62.7-95.5 mm, Hon- 

 duras, ANSP 103299, 3, 72.0-129 mm, Nicaragua; 

 ANSP 97654, 1, 174 mm, Venezuela. 



Hollardia meadi Tyler: ANSP 97396, 1, 64.5 mm. 



Johnsonina eriomma Myers: ANSP 97750, 2, 75.5-85.5 

 mm, Panama; ANSP 103149, 2, 60.1-66.3 mm, 

 Panama; ANSP 103300, 2, 67.0-68.0 mm, Puerto Rico. 



Macrorhamphosodes platycheilus Fowler: ANSP 

 100862, 1, ca. 85 mm (posterior part of body absent), 

 Bay of Bengal; ANSP 100865, 2, 80.3-85.3 mm. Bay of 

 Bengal; USNM 93482, 1, too disintegrated to measure, 

 Philippines. 



Macrorhamphosodes uradoi (Kamohara): ANSP 

 101254, 2, 69.9-114 mm, Japan. 



Parahollardia lineata (Longley): ANSP 100473, 1, 45.7 

 mm, Florida; ANSP 93375, 1, 62.2 mm, Florida; ANSP 

 102144, 1, 82.0 mm, Florida; ANSP 102145, 1, 86.1 

 mm. South Carolina; ANSP 97637, 3, 79.4-84.4 mm, 

 Louisiana. 



Parahollardia schmidti Woods: ANSP 100866, 5, 48.7- 



62.5 mm, Honduras; ANSP 103302, 2, 62.0-74.0 mm, 

 Nicaragua; ANSP 100128, 4, 56.8-77.8 mm, Nicara- 

 gua. 



Paratriacanthodes retrospinis Fowler: ANSP 103285, 1, 

 85.3 mm, Mozambique. 



Triacanthodes anomalus (Schlegel): ANSP 101257, 4, 

 50.6-59.7 mm, Japan; ANSP 101256, 1, 71.5 mm, 

 Japan; SU 49435, 1, 91.0 mm, Formosa. 



Triacanthodes ethiops Alcock: USNM 93486, 2, 55.3- 

 63.7 mm, Philippines; ANSP 103286, 1, 76.1 mm, 

 Kenya. 



Tydemania navigatoris Weber: ANSP 100861, 6, 58.8- 

 67.0 mm. Bay of Bengal; ANSP 100863, 2, 60.1-62.2 

 mm, Bay of Bengal; ANSP 102137, 1, 63.3 mm. Bay of 

 Bengal; USNM 93471, 1, ca. 95 mm, dry skeleton, 

 Philippines. 



Triacanthidae 



Pseudotriacanthus strigilifer (Cantor): SU 41732, 1, 



79.0 mm, India; ANSP 89387, 4, 119-145 mm, 

 Thailand. 



Triacanthus biaculeatus (Bloch): SU 27746, 2, 113-118 

 mm, Borneo; ANSP 76585, 1, 124 mm, China; SU 

 41730, 1, 25.6 mm, India; GVF reg. no. 2655, 3, 10.9- 



19.1 mm, Thailand. 



Triacanthus nieuhofi Bleeker: ANSP 102982, 1, 108 

 mm, possibly Australia. 



Tripodichthys angustifrons (Hollard): ANSP 98719, 1, 

 137 mm, Australia. 



Tripodichthys blochi (Bleeker): ANSP 103298, 3, 55.1- 

 88.9 mm, locality unknown; ANSP 103301, 3, 69.4-97.3 

 mm, locality unknown; ANSP 63429-54, 11, 18.4-50.9 

 mm, Philippines; ANSP 63476, 1, 81.0 mm, Philip- 

 pines; ANSP 63421-25, 5, 24.3-105 mm, Philippines; 

 SU 26930, 2, 92.0-107 mm, Philippines. 



Tripodichthys oxycephalus (Bleeker): ANSP 102325, 1, 

 125 mm. Bay of Bengal. 



Trixiphichthys weberi (Chaudhuri): ANSP 102136, 1, 



29.6 mm. Bay of Bengal; ANSP 101389, 3, 101-119 

 mm, Bay of Bengal. 



