CIEGULATOEY SYSTEM. 149 



pairs will be better seen at a later stage of the 

 dissection. 



The roots of the arteries are rather small and trans- 

 parent, and hence difficult to see. They arise 

 from the two ends of the heart, and should be 

 noticed at the present stage of the dissection, 

 though the arteries themselves are best seen in 

 an injected specimen, and will be described later 

 (p. 159). 



i. From the anterior end of the heart arise a 

 median ophthalmic artery and a pair of 

 antennary arteries ; and behind and below 

 these a pair of hepatic arteries. 



ii. From the hinder end of the heart arises the 

 large median dorsal abdominal artery, and 

 immediately below this the large median 

 sternal artery, which latter can be better 

 seen at a later stage. 



Fig. 35. — ABtaeus fluviatilis, var. nobilis. Dissection of a male from 

 the right side. The right side of the body-wall with its appendages, 

 and the right side of the oesophagus, stomach, and mesenteron, have 

 been removed. The thick black line represents the cut edge of the 

 cuticle, (c. H. H.) 



A, eiidopliraginal skeleton, AA, anteunary artery. AIT, ' auditory ' sac. 

 B, basipodite of the tenth appendage. BD, aperture of left bile-duct into the 

 mesenteron. C, cardiac chamber of the stomach. CM, csecum. CO, cardiac 

 ossicle. CP carpopodite of tenth appendage. CP 9. carpopodite of ninth 

 appendage. CX, coxopodlte of tenth appendage. D, dactylopodite of the 

 same. DAj dorsal abdominal artery. E, eye. G 1, supra-cesophageal gan- 

 glion. Gr 2, sub-cesophageal ganglion. Gr 3, second post- oesophageal ganglion. 

 Gr 8, last thoracic ganglion. G- 14, last abdominal ganglion giving ofE posterior 

 visceral and other nerves. H, right lateral ostium of the heart. HA, hepatic 

 artery. I, proctodoeum. IS, ischiopodite of thetenth appendage. K, iiidiiey. 

 L, liver. LT, lateral tooth. M, meropodlte of the tenth appendage. MS, 

 raetastoma. MT, median tooth. M 8, meropodite of the eighth appendage. 

 M" 1, TiT 3, etc. endopodites of first, third, etc., appendages. OA, ophthalmic 

 artery. OC, lefb para-oesophageal connective: the greater part of the right 

 one has been removed. OE, oesophagus. PL 16, pleurou of the sixteenth 

 segment. PO, pyloric ossicle. PPO, E#epyloric ossicle. PR,, propodite of 

 thetenth appendage. PTO, pterocardiac ossicle. PY, pyloric chamber of 

 the stomach. P 3, P 4, P 5, protopodites of the third, fourth, and fifth 

 appendages. B-, rostrum. SA, sternal artery. S 16, sternum of the sixteenth 

 segment. T, testis: the right anterior lobe has been removed. T16, tergutu 

 of the sixteenth segment. U, ureter. TJA, aperture of the ureter. UCO, 

 urocardiac ossicle. V, ventral thoracic artery. VA, ventral abdominal artery. 

 VD,left vas deferens : the right one has been cut off short. VDA, aperture of 

 the left vas deferens. X 1, X 2, etc., exopodites of first, second, etc., appendages. 

 ZO, zygocardiac ossicle. 14, the fourteenth appendage. 



