262 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



THIRD SUBGENUS. 



Seniles under the tail but none in front of the eyes. 



10. L'OSTRACIOX TRIGOXE (= 0. tngoHHs). 



11. L'OSTRACIOX D0U13LE-AIGUILLON (= 0. hicaiiclalis), 



FOURTH SUBGENUS. 



Spines in front of the eyes and under the tail. 



12. L'OSTRACIOX QUATRE-AIGUILLOXS (= 0. quadricomis). 



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



14. L'OSTRACIOX QUADRANGULAIRE (= 0. COmutum). 



15. L'OSTRACIOX DROMADAIRE (= 0. turritus). 



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

 based entirely upon the shape of the 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 OstraciXzE. Body mailed witli angular jjlates. 

 OsTRACiOX'^. 'Body qfladrangular, destitute of spines. 

 Tetrosomus. Body (xuadi-angular ; sjiines on the back and belly. 

 *Body triangular. 

 Platycanthus. Body -witli several flattened bony obtuse spines. 

 Lactophrys. Front and vent witli two liorn-Iike, acute spines. 

 Ilhincsomus. Body without spmcs, often scored as in the Balistinw. 



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. Ostracix^. 

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

 covered by auguiated bony plates, soldered at their sutures; dorsal fin one; no ven- 

 tral fin ; caudal rounded. 



OsTRACiox, Linn. Body quadrangular ; destitute of spinal iirocesses. 



0. cul)icus, Bloch. pi. 137. nasus, lb. pi. 138. 

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



T. turritus, Bl. pi. 136. 

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

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

 bling horns. 



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



hicaudalis, lb. 132. qUadricornis, lb. 134. 



Ehinesomus, Sw. Body triangular, entirely destitute of spines, and often scored or 

 reticulated as in Balistes. 



E. triqueter, Bloch. pi. 130. concatenatus, lb. i>l. 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 by the 

 diflerent kinds of type employed by the- author. But for the direct 



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

 Eeptiles | or | Monocardian Animals. | By "William Swainson, F. R. S., F.L. S., &c., &c. 



j I in two volumes. | | Vol. I (II). (Vignette.) | London : | Printed for 



Longman, Ormc, Brown, Green, and Longmans, Paternoster Row, | and John Taylor, 

 Upper Gower St., | 1839. Vol. ii, pp. 193, 323. 



