-------+---------+--------------------------------------------+---------- Preanal|Number | |Per cent scales |of | CAUSE |of |specimens| |occurrence -------+---------+--------------------------------------------+---------- | |Scale rows seven and eight on left fuse | 14 | 10 |within the last five ventrals | 4.1 | | | | |Scale row two on the right is lost adjacent | 14 | 1 |to the penultimate ventral | 0.4 | | | | |Scale row eight on the left divides adjacent| 16 | 1 |to the last ventral | 0.4 | | | | |A scale row is added on the right adjacent | 16 | 1 |to and anterior to the anal plate | 0.4 | | | | |A scale row is added on each side adjacent | 17 | 1 |to and anterior to the anal plate | 0.4 -------+---------+--------------------------------------------+---------- The complete dorsal scale formula for KU 83620, a male, is as follows: 6 + 7(2) + 7(4) 6 + 7(11) 15 --------- 13 --------- 14 --------- 15 ---------- 13 --------------, 6 + 7(2) +7(5) 6 + 7(11) 6 = 6 + 7(17) 14 ------------- 13---------, 6 + 7(18) +7(25) + 7(26) 6 + 7(38) +7(39) 14 ---------- 15 ---------- 14 ------------ 13---------- 14----------, 6 + 7(36) +7(42) 15 --------- 14 ---------, -6(45) +7(53) 7 + 8(67) + 7(69) 15 ------------ 14 ----------- 15 ----------- 14 ---------- 15----------, 6 + 7(90) +7(93) 6 + 7(99) 14 ------------ 15(122). + 7(100) Specimen 83620 is the only one for which we have determined the complete dorsal scale formula. Obviously the formula is complex, and possibly the specimen is atypical in this regard. Nevertheless, addition and reduction of scale rows is apparent on other specimens and can be easily observed by examining specimens under a dissection microscope. Anal plate Of the 246 specimens examined, 232 (94.3%) have the anal plate divided. Of the 14 specimens having undivided anal plates, four have an incomplete groove anteriorly in the plate. Ventrals [Illustration: FIG. 2. Number of ventrals in females and males of _T. gracilis_.]