MODERN SYSTEM. 
98 
Pencils trisulcatus. Leach, Trans. Linn. Soc. xi. 347 . — Supp. to Eneycl. 
Brit. l. 421. — Mai. Podoph. Brit. tab. 42. 
Inhabits the Welsh Sea. 
Stirps 4. — F. eternal antenna; inserted below the internal; internal 
ones with three setae. (External lamella, of the tail composed of but 
one part) 
Genus 85. PAL/EMON. Fair., Latr., Bose, Leach. 
Four anterior legs didactyle : anterior pair smaller than the second pair : 
external double palpi with the last joint shorter than the preceding 
joint. 
Sp. 1. Pal. serratus ( common Praam). Rostrum ascending above, with 
from six to eight teeth, the apex emarginate ; below with from foot 
to six teeth. 
Astacus serratus. Penn. Brit. Zool. iv. 19. (pi. 16. Jig. 28.) Cancc' 
(Astacus) Squilla. Herbst, ii. 55. tab. 27. (jig. 1.) Palasmon Squill*- 
Latr. Gen. Crust, et Insect, i. 54. Leach, Ediii. Jincycl. vii. 401 . Par 
lremon serratus. Leach , Trans. Linn. Soc. xi. 348. — Supp. to Encyel 
Brit. i. 421. — Mai. Podoph. Brit. tub. 43. jig. 1 — 10. 
Variety a. Rostrum with six teeth above. 
Subvariety 1. Rostrum beneath with four teeth. 
2. five teeth. 
Variety |3. Rostrum above with seven teeth. 
Subvariety 1. Rostrum beneath with four teeth. 
— 2. five teeth. 
3. six teeth. 
Variety y. Rostrum with eight teeth above. 
Subvariety 1. Rostrum beneath with tour teeth. 
2. — — five teeth. 
3. six teeth. 
■■ Although all the above varieties are common, yet /3 occurs m°- 
frequently. In some may be seen the upper edge of the rostrum \viw 
ten, the lower with five teeth ; and both edges with but three teeth 
The apex is generally notched above, and in two specimens, wbw 
may be considered a rare occurrence, the point has been found et*' 
tire. The situation of the teeth on tire upper edge is variable, but 1,1 
most instances the second tooth is at a greater distance from the fi<* 
than the rest, which are generally equidistant, and rarely extend 
beyond the middle, the rostrum from that part being edentate, 
the exception of the emarginate apex.” . , 
Herbst, Latreille, and Leach, formerly considered this spedh 
as Cancer Squilla of Linne; but Dr. L. has, since the publication 
the error, met with the true C. Squilla of that author, and has 4* 
