SOME ASPECTS OF BIOCHEMICAL DIVERSITY 293 



(Arenicola, Eunice, Cirrhatulus, Nephthys, Nereis, Nais, Ophelia, Marphysa, 

 etc.). In the Phyllodocidae, Syllidae and Chaetopteridae, the blood is 

 colourless. No case is known of an Annelid having a blood containing an 

 intracellular oxygen-carrier. Where there is haemoglobin in the coelomic 

 fluid of an Annelid, the oxygen-carrier is always contained in a blood 

 corpuscle. This is the case for a number of Polychetes not possessing a 

 circulatory system, e.g. the Capitellidae, Glyceridae and Terebellidae 

 Polycirrus hematodes. In other Terebellidae such as Travisia forbesii or 

 Terebella lapidaria, there is also dissolved haemoglobin in the coelomic 

 corpuscles. Among the Oligochaeta, we generally find colourless blood 

 in the circulatory system of the Enchytraeides (though some of them, 

 such as Pachydrilus lineatus, have haemoglobin in their blood). In many 

 others of the Oligochaeta it contains dissolved haemoglobin: in Lumbricus, 

 Tubifex, Limnodrilus, Lumbriculus, etc. When we come to the Hirudinea, 

 we find dissolved haemoglobin in the blood of the Gnathobdellides 

 (Hirudo, Aulastoma, Nephelis, etc.) and colourless blood in the Rhynchob- 

 dellides [Pontobdella muricata, Branchiobdella astaci, etc.). 



In the nemertian or the turbellarian worms, we sometimes find haemo- 

 globin-containing corpuscles in the blood [Derostoma, Syndesmis, Dre- 

 panophorus, Polio). 



The Echiurioidea are sometimes considered as aberrant worms. They 

 are not segmented and only possess a few chaetae arranged differently from 

 that in the Annelids and their body consists of two parts, a retractile preoral 

 lobe and the body proper. In the coelomic cavity of many Echiurioidea 

 nucleated corpuscles containing haemoglobin are found. Moreover the 

 coelomic fluid of the Echiurioidea is the only fluid in their milieu interieur 

 for they are devoid of a circulatory system. 



Among the molluscs, we find haemoglobin-containing corpuscles in the 

 blood of numerous Lammellibranchs (belonging to the genera Pectunculus, 

 Glycimeris, Cutellus, Area, Gastrana, Tellina, Solen, Poromya, Capsa, 

 Astarte, etc.) and in the coelomic fluid of certain Amphineura, the Neomen- 

 ians. In a Gastropod, Planorbis, the blood contains dissolved haemoglobin. 



Only very exceptionally do we find haemoglobin in the Arthropods. 

 Among the Crustacea, many species of small size are without an oxygen 

 carrier whilst others have haemocyanin in the blood. It is only in the group 

 of the Entomostracea [Apus, Branchipus, Artemia, Daphnia, Chirocephalus, 

 Lernanthropus, Clavella, Congericola) that we find bloods containing dis- 

 solved haemoglobin. When we come to the insects, who, in order to bring 

 oxygen to the cells, have had recourse to a direct transfer from the air via the 

 tracheae, we find that their blood is without an oxygen carrier, with the re- 

 markable exception of the blood of the larvae of certain of the Chironomides. 

 The similarity to haemoglobin of the red pigment dissolved in the blood 

 of the larva of the Diptera Chironomus, was demonstrated by Rollet in 1861. 



