358 



MISS B. J. BECK ON THE MUSCULAE 



exactly similar to the anterior pericardio- ventral muscle (136), except that it runs on 

 the posterior instead of the anterior side of the dorso-ventral muscle (71). 



The pericardium is not continued into the five subsequent segments of the metasoma, 

 and accordingly we do not find there any muscles representing the veno-pericardiacs of 



the mesosoma and first metasomatic segment. 



I. 



n. 



m.- 



vn.- 



xm." 



A. 



B. 



C. 



D. 



E. 



F. 



G. 



H. 



K. 



L. 

 N.C. 



v.c. 



v.s. 



ac. 

 am. 



ap. 

 are. 



Mm. 

 car. 



ce. 

 eg. 

 dr. 

 dv. 



Reference to letters in Plates 



Chelicera, first appendage. 



Chela, second appendage. 



-Ti. Four ambulatory appendages. 



-III. Six segments of mesosoma. 



-xvin. Six segments of metasoma. 



First coxal entosclerite. 



Second coxal entosclerite. 



Anterior third coxal entosclerite. 



Posterior third coxal entosclerite. 



Anterior fourth coxal entosclerite. 



Posterior fourth coxal entosclerite. 



Fifth coxal entosclerite. 



Preoral entosclerite. 



Postoral entosclerite. 



Carino-stornal entosclerite. 



Canal in plastron through which nerve-cord 



gc. 



go. 

 le. 



Ventral portion of carapace turned under 



anteriorly (transparent). 

 Vascular space in pericardio- ventral muscle. 

 Alimentary canal. 

 Arthrodial membrane, covering the body 



between the chitinous plates. 

 Anterior process of plastron. 

 Arterial canal-aperture in posterior flap of 



plastron through which the dorsal vessel 



runs. 

 Camerostome or upper lip. 

 Carapace. . 

 Central eyes. 

 Coxal glands. 

 Dorsal ridge of plastron. 

 Dorsal vessel (anterior continuation of 



heart). 

 Gastric canal-aperture in posterior flap of 



plastron, through which the alimentary 



canal runs. 

 Genital operculum (seventh appendage). 

 Lateral eyes. 



■ng. 



P- 

 pa. 

 pec. 



LXXVII., LXXVIII., LXXIX. 



fc, h^ Is.^ Isy Lung-sacs (blood-containing envelopes of 

 the lung-books) in four last segments of 

 mesosoma. 

 Imp. Lateral median process of plastron. 

 m. Mouth. 

 to'. Aperture in flap of plastron through which 



muscle 83 passes. 

 m^. Aperture in flap of plastron through which 



muscle 65 passes. 

 mJ. Divisions between muscles. 

 met. Thoracic metastcrnite. 

 mf. Muscular fibres. 

 lie. Nerve-cord. 



Nerve-ganglion. 

 Pericardium. 

 Postanal spine. 

 Pecten (eighth appendage). 

 pf. Posterior flap of plastron. 

 ph. Pharynx. 

 pi. Plastron. 



pp. Posterior process of plastron. 

 snp. Subneural process of plastron. 

 spc. Suprapectinal chondrite. 

 sts. Sternal sclerite on which pectincs are carried 

 in second segment of mesosoma. 

 x. Cut edge of carapace. 

 y. Cut edge of tergites. 



1. Antero-posterior muscle (prosoma). 



2. Arthrodio-tergal obliquus muscle (prosoma). 

 3-8. Antero-posterior muscles (mesosoma). 

 9-14. Arthrodio-tergal obliquus muscles (meso- 

 soma). 



15-20. Latero-dorsal muscles (mesosoma). 



21-24. Median antero-posterior muscles (meso- 

 soma). 



25-30. Lateral antero-posterior muscles (mesosoma). 



31-34. Arthrodio-sternal obliquus muscles (meso- 

 soma). 



35-38. Post-stigmatic muscles (mesosoma). 



