38 ARKIV FÖR ZOOLOGI. BAND 13. N:0 25. 



Fig. 3. — Six views of blood-corpuscles fixed in 40 % formalin 

 and stained. 



Fig. 4. — Two blood-corpuscles from tlie Polian vesicle fixed 

 in 40% formalin; the too strong fixative liaving forced a series of 

 whitish globulets towards the periphery; stained by iron-alum hse- 

 matoxyline. 



Fix. 5. — Four blood-corpuscles treated in the same way as the 

 preceding, but decoloured by threatment with iron-alum; two kinds 

 of granules being visible. 



Fig. 6. — Two anomalous living rhomboids. 



Fig. 7. — Four more or less disfigured living rhomboids and stars. 



Fig. 8 and 9. — Two rhomboids fixed, stained and mounted in 

 balsam; fig. 9 presents an interiör rhomboid left af ter decalcification. 



Figs. 10 — 13. — Different views of rhomboids, drawn from the 

 living. 



Plate 5. 



Figs. 1 — 3. — Crystals from the coelomic cavity of Stichopus 

 tremula, drawn from the living; fig. 1 = rhomboid = 15,2 ]X; fig. 2 

 = står =11,4 [i.; fig. 3 = side-view of a står. 



Figs. 4 — 7. — Crystals from the coelomic cavity of Cucumaria 

 hyndmani fixed in Perényi's fluid, stained and mounted in balsam; 

 fig. 4 = rhomboid = 18,7 [i; fig. 5 = rhomboid =13,6 [J-; fig. 6 = 

 rhomboid = 11,9 [J^ fig- 7 = står =13,6 [J-. 



Figs. 8 — 10. — Crystals from the coelomic cavity of Cucumaria 

 hyndmani, drawn from the living; fig. 8 = two stars, one of them 

 deformed; figs. 9 — 10 = rhomboids varying in length from 20,9 p- 

 to 26,6 [J.. 



Figs. 11 — 12. — Red blood-corpuscles from the coelomic cavity of 

 Thyone fusus, drawn from the living; length from 15,2 {J- to 22,8 (J-; 

 fig. 12 = side-views. 



Fig. 13. — Red blood-corpuscles from the Polian vesicle of Thyone 

 fusus, fixed and stained in dilute osmic acid; length = 22,8 {i and 

 38 \i. 



Figs. 14 — 15. — Three finely granulated red corpuscles from the 

 coelomic cavity of the same animal, after treatment with 40 % forma- 

 lin and picro-carmine; fig. 14 = cells with protuberances ; length = 

 17 [i. to 22,1 [J.. 



Fig. 16. — Two red blood-corpuscles from the same species, fixed, 

 stained and mounted in balsam, the two strong fixative having forced 

 series of whitish globulets towards the periphery; magnitude =17 

 [J. and 11,9 [1. 



Fig. 17. — Hyaline, minute corpuscles from the coelomic fluid 

 of Thyone fusus, measuring 2,5 {J-, 4,3 [i, 5,i [J-, etc; probably to be 

 considered as protuberances or remains of them, disentangled from the 

 bood-corpuscles. 



Fig. 18. — Four hyaline, fusiform corpuscles from the coelomic 

 fluid of Thyone fusus; probably fragment of shattered tissues?; great- 

 est length = 19 [X. 



