LEVITON, BROWN, & SILER: PHILIPPINE VENOMOUS SNAKES 
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precloacal scale (often termed anal scale or plate): enlarged scale following last ventral scale that 
overlies the cloacal or vent opening; scale may be single or paired, 
preocular scale: one or more scales that border the front edge of the eye orbit (but see also loreal 
scale above). 
proximal: next to or nearest to point of origin or attachment; toward the front end or head region 
from a refemce point that farther behind. 
scales, scutes, shields: frequently used interchangeably. However, scutes and shields are usually 
larger structures than scales, which term is most often used to described the smaller stmcture 
that adorn the dorsum of the body. Scutes and shields are terms usually reserved to describe the 
belly scales as well as the scales on the head and chin. To avoid confusion, we have used the 
term scale(s) to describe all the epidermal structures on the snakes, 
scale rows (body): scales on the upper and sides of the body, usually arranged in parallel longtiu- 
dinal rows; the number of transverse rows (rows across the body) are counted beginning with 
the first row on the side that is in contact with the enlarged ventrals and counting to the oppo¬ 
site side. 
sensory pit: a deep depression on the side of the head between the nostril and the eye of some 
viperine snakes (pitvipers) that contains an infrared (heat) sensory receptor at its base; in 
pitvipers the pit occurs on each side in the loreal scale, 
snout-vent length: straight-line distance measured from the tip of snout to the posterior edge of 
the anal orifice. 
subcaudal scales: enlarged plate-like scales on the underside of the tail, usually paired but occa¬ 
sionally undivided. 
subocular scale(s): one or more scales lying between eye and upper labial scales [^.v.]. 
tail length: straight-line distance measured from the vent to the tip of the tail, 
temporal scales: scales on the sides of the head behind the eye and the postocular scale, 
total length: straight-line distance from the front of the snout to the tip of the tail, 
transverse (across): set crosswise, at right angles to the longitudinal or long axis of the body, 
extending from side to side. 
vent: opening of the cloaca to the outside, covered by an enlarged precloacal scale [^.v.]. 
ventral (below): ventrum, underside, or toward the underside (see also ventral scales), 
ventral scales: transversely enlarged plate-like scales on the underside of the tmnk extending from 
the throat to the precloacal scale; among sea snakes, sometimes indistinguishable from adjacent 
scales. 
ventrolateral: a narrow region along the lower side where ventrum and side of trunk meet, 
ventrum: underside of tmnk from neck to vent. 
