262 PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



THIRD SUBGENUS. 



Spines under the tail hut none in front of the eyes, 



10. L'OSTUACION TRIGONE (= 0. triijonus). 



11. L'OSTRACION DOUBLE-AiGUiLLON (= 0. hicaudalis). 



FOURTH SUBGENUS. 



S2nnes in front of the eyes and under the tail. 



12. L'OSTRACION QUATRE-AiGUiLLONS (= 0. quadricomis). 



13. L'OSTRACION LISTER (= 0. quadricomis). 



14. L'OSTRACION QUADRANGULAIRE (= 0. COmutiUn). 



15. L'OSTRACION DROMADAIRE (=: 0. turritus). 



The next attempt at a subdivision was by Swaiuson in 1839,* and was 

 based entirely upon the shape of tlie carapace. The peculiar features 

 of this arrangement can most easily be shown by quoting in full from 

 the preliminary synopsis (p. 194). 



1. Sub-family Ostracin^. Body mailed with angular plates. 

 OSTRACION. Body quadrangular, destitute of spines. 

 Tetrosomus. Body quadrangular ; si>ines on tlie back and belly. 

 *Body triangular. 

 Platycanthus. Body Avith several flattened bony obtuse spines. 

 Lactophrys. Front and vent -with two liorn-like, acute spiues. 

 Bhinesomus. Body without spines, often scored as in the BaUstince. 



In the main body of the "Classification of Fishes, etc." (pp. 323-324), 

 the definitions of genera and subgenera were expanded as follows : 



I. Sub-fam. Ostracin^. 

 Body smooth, quadrangular in the typical and triangular in the aberrant groups, 

 covered by angulated bony j)lates, soldered at their sutures ; dorsal fin one; no ven- 

 tral fin ; caudal rounded. 



Ostracion, Linn. Body quadrangular ; destitute of spinal processes. 



0. chMcus, Bloch. pi. 137. nasus, lb. pi. 138. 

 Tetrosomus, Sw. Body quadrangular ; armed with spines on the back and belly. 



T. turritns, Bl. pi. 136. 

 Lactophrys, Sw. (fig. 102). Body triangular, armed with strong spiues, curved 

 backward just before the anal fin, and generally with two others, resem- 

 bling horns. 



L. trigonus, Bl. pi. 135. eornutus, Bl. 133. 



hicaudalis, lb. 132. quadricomis, lb. 134. 



Bhinesomus, Sw. Body triangular, entu-ely destitute of spines, and often scored or 

 reticulated as in Batistes. 



R. iriqueter, Bloch. pi. 130. concatenatus, lb. pi. 131. 

 Platycanthus, Sw. {Acarana, Gray). Compressed, subtriangular, with broad ob- 

 tuse plates or spines scattered over the body and eyes. 

 P. auratus, Shaw. Nat. Miss. pi. 338. 



It would be interesting to know what relations are indicated hy the 

 different kinds of type emi^loyed by the author. But for the direct 



* 1839. SwAiNSON, William. The Natural History | of | Fishes, Amphibians, and 

 Reptiles | or | Monocardian Animals. | By William Swainson, F. E. S., F. L. S., &c., &c. 



I I in two volumes. | | Vol. I (II). (Vignette.) [ Loudon : | Printed for 



Longman, Ormo, Brown, Green, and Longmans, Paternoster Eow, | and John Taylor, 

 Upper Gower St., | 1839. Vol. ii, pp. 193, 32:'.. 



