OVERVIEW 
The Registry of Tumors in Lower Animals (RTLA) facilitates the 
study of neoplasms and related disorders in invertebrate and poikilo- 
thermic vertebrate animals by serving as a specimen depository, a diag¬ 
nostic center, an information center, and a research group. 
Two hundred three accessions (many with multiple specimens) from 
13 countries were entered into the Registry’s permanent collection in 
1978. As shown in Table 1, nearly one-half were neoplasms which oc¬ 
curred, in decreasing numbers, in bony fish, reptiles and mollusks 
(same number), amphibians, sharks and arthropods (same number). 
TABLE 1 
Distribution of lesions among specimens accessioned 
Phylo¬ 
genetic 
group 
Type of disease 
Neo¬ 
plastic 
Non-neo- 
plastic 
Undeter¬ 
mined 
Total 
Reptile 
8 
16 
0 
24 
(12%) 
Amphibian 
6 
9 
0 
15 
(7%) 
Bony fish 
65 
66 
2 
131 
(65%) 
Shark 
1 
5 
0 
6 
(3%) 
Mollusk 
8 
14 
1 
23 
(11%) 
Arthropod 
1 
1 
0 
2 
(1%) 
Total 
83 (41%) 
117 (58%) 
3 (1%) 
203 
(100%) 
Percent of those 
diagnosed 
(42%) 
(58%) 
Probably the most significant advance of the year was the demonstra¬ 
tion that the ”x-cells" in parabranchial lesions of cod, and by extrap¬ 
olation, in the skin lesions of various flatfish (RTLA 2039), goby (RTLA 
1897, 2023-2025, 2031, 2033), and other fish species (RTLA 2000) have 
mitoses and other features which are atypical for vertebrates but are 
