576 



ZOOLOGY 



SECT. 



muscles (oil. stern.), confined to the abdomen ; (3) and longitudinal 

 tergal muscles, best developed in the abdomen. The various 

 segments of the limbs are capable of being flexed or extended on 

 one another, as in the Crayfish, by the contractions of special 

 muscles. The wings are little used, the female cockroach being 

 incapable of flight, and the male not a strong flier, and accordingly 

 the wing muscles are not very strongly developed. 



Between the body wall and the alimentary canal is a cavity 

 taking the place of the coelome, but in reality forming a specially 



sected 

 lents ; 



Fir,. 457. Semi-diagrammatic view of the internal organs of a female Cockroach, dissect* 

 from the left side. The heart is not represented. . abd.l, abd.5 first and fifth abdominal segments ; 

 a/i anus ; ant. antennary nerve ; brn. brain ; cer. anal cercus ; CMC. caeca ; coll. colleterial 

 glands ; cr. crop ; gizz. gizzard ; yon. gonapophyses ; infr. gang, sub-cesophageal ganglion ; 

 int. intestine ; Ib. pip. labial palp ; l.ov. left ovary ; malp. malpighian tubes ; mx.plp. maxillary 

 palp. ; od, points to the external opening of the median oviduct (vagina) ; ces. oesophagus ; 

 i-.oc. right ovary; sal. gld. salivary glands ; sal. rcc. salivary receptacle (left); sal. du. salivary 

 ducts, indicating the point at which the median duct of the salivary glands unites with tl 

 median duct of the salivary receptacles ; spir. spiracles ; st. 7, sternum of the seventh se 

 ment ; te. 10, tergum of the tenth segment ; tk l , th^, 7*3, first, second, and third segments 

 the thorax. 



developed part of the blood-vascular system (hsemoccele). This 

 is bounded externally by an irregular wall, formed of a mass of 

 polygonal cells constituting the fat body. 



Digestive system. The mouth opens into a buccal rcc if// 

 which receives the ducts of the salivary glands (Fig. 457, sal. gld.). 

 Each gland is divided into two lobes, each made up of numerous 

 ramifications. In close relation to each gland is an elongated 

 thin-walled sac the salivary receptacle (sal. rec.). The duct given 

 off from the salivary receptacle joins that of the opposite side, 

 and the median duct thus formed is joined by a single duct (sal. 



