1.30 DISTRIBUTION OF HAEMOGLOBIN IN INVERTEBRATA. [BOOK I. 



without the intermediation of any special arrangement such as is 

 represented by the haemoglobin of the vertebrate coloured corpuscles. 



In the Invertebrata whose blood is coloured, we have, however, 

 undoubtedly, a clear indication of the blood discharging respiratory 

 functions, for such blood, when red, contains oxy-haemoglobin,and when 

 of other colours, sometimes undoubtedly does contain matters which 

 are capable of acting as oxygen carriers. 



The following are the most important facts which have been 

 discovered in reference to the chemical composition of the blood of 

 invertebrate animals : 



Distribution of Haemoglobin through the vascular liquids of various groups 



of Invertebrata. 



Our knowledge of this subject is mainly derived from the researches of 

 Professor Ray Lankester 1 . The following are the chief conclusions to 

 which he has arrived. 



Haemoglobin is contained 



1. in special corpuscles : 



a. In the perivisceral fluid of some species of the Vermian genera, 

 Glycera, Capitella and Phor&nis. 



b. In the blood of the Lamellibranchiate Mollusk, Solen legumen. 



2. Diffused in a vascular or ambient liquid : 



a. In the peculiar vascular system of the Chaetopodous Annelids very 

 generally, but with apparently arbitrary exceptions. 



b. In the vascular system (which represents a reduced perivisceral 

 cavity) of certain Leeehes, but not of all (Nephelis, Hirudo). 



c. In the vascular system of certain Turbellarians as an exception 

 (Polia sanguirubra). 



d. In a special vascular system (distinct from the general blood-system) 

 of a marine parasitic Crustacean (undescribed) observed by Pro- 

 fessor Eclouard van Beneden.. 



e. In the general blood-system of the larva of the Dipterous Insect 

 Cheironomus. 



f. In the general blood-system of the Pulmonated Mollusk Planorbis. 



g. In the general blood-systems of the Crustaceans Daphnia and 

 Cheirocephalus. 



In reference to Planorbis, Mr H. C. Sorby has made observations which 

 lead him to doubt very strongly whether the red colouring matter be really 

 haemoglobin 2 , Mr Sorby's doubts are based (1) upon the fact that 

 the measurements of the bands in the spectrum of the blood of Planorbis 

 differed slightly from those of oxy-haemoglobin ; (2) that the red colouring 

 matter in the blood of Planorbis seemed to resist the action of decomposing 

 reagents (such as acids) longer than haemoglobin. According to Sorby 

 the following are the centres of the bands of normal haemoglobin and of 



1 Lankester, Op. cit. t p. 76. 



. 2 H. C. Sorby, " On the Evolution of Haemoglobin." Quarterly Journal of 

 Microscopical Science. Vol. xvi. N. S. (1876) p. 76 et seq. 



