FRESH-WATER FISHES OF SIAM, OR THAILAND 499 



Outstanding and invariable physical features of the gobies are the 

 insertion of the ventral or pelvic fins in the thoracic region, under or 

 in advance of the pectorals, and the absence of a lateral line. The 

 shape of the ventral fins is a prime character used in the classification 

 of families, genera, and species in combination with the shape and 

 structure of the fins, the dentition, and the squamation. Osteological 

 characters of the order include the small number of vertebrae (not 

 exceeding 37) and reduction or even vestigial condition of the scapula 

 and coracoid. 



The number and arrangement of the cutaneous papillae and pores 

 on the head in the gobies are very important in the study of the genera 

 and species. The subject is worthy of much more attention than has 

 heretofore been given except by a very few modern ichthyologists, 

 among whom may be especially mentioned Luigi Sanzo (1911) and 

 Isaac Ginsburg, of the United States Fish and Wildlife Service. In 

 the present work it has not been possible to devote to the subject the 

 detailed study that is required in order to cover it thoroughly, but it 

 is known that many of the Oriental gobies, including those of Thailand, 

 present features of special interest in the development of the systems 

 of pores and papillae, and it is hoped that qualified students may find 

 opportunity to devote the necessary time and effort to the elucidation 

 of these organs, not neglecting their functions. 



The nomenclature, taxonomy, and classification of many Oriental 

 gobies have been much involved. Important contributions to the 

 classification of Pacific and Oriental gobies have been made by Jordan, 

 Scale, Snyder, Fowler, Herre, Koumans, and others, but much remains 

 to be done before a wholly satisfactory correlation of Indian, Burmese, 

 Thai, Malayan, Indo-Australian, Philippine, and Chinese forms can 

 be achieved. 



In no other order of fishes does there exist such an opportunity to 

 add to the knowledge of the fish fauna of Thailand as in the gobies. 

 It is certain that many new or rare forms remain to be discovered, 

 and even among well-known species much valuable information may 

 be acquired in regard to habits, spawning, growth, variation, and 

 other characteristics. 



Mention may be made here of a paper of special interest by Prof. 

 A. S. Pearse (1933), dealing chiefly with four goby species common on 

 the mud beaches near the mouth of the Menam Chao Phya. The gobies 

 are considered with reference to their ecology, evolutionary tenden- 

 cies, and parasites, and the following paragraphs are extracted from 

 Pearse's very valuable paper : 



The beach-skipping gobies are of particular interest because they are at pres- 

 ent in the very act of becoming land animals. They live on wet, mucky beaches 

 but are veritable terrestrial vertebrates and may live for several days out of 



