480 EDWIN S. GOODRICH. 



been added since. ^ What concerns us at present is the 

 evidence of continuity between the contractile and non- 

 contractile systems in Hirudo. 



The earlier authors all believed in the continuity, and based 

 their conclusions mainly, if not entirely, on injection. Jaquet 

 (5), who has recently re-investigated the blood system of 

 Hirudo by means of injections, confirms this view, describing 

 small branches communicating from the longitudinal vessels 

 to the longitudinal sinuses in front, and also from the lateral 

 vessel to the perinephrostomial sinus. But the evidence 

 brought forward by these authors is not clear and convincing, 

 and, in fact, they do not treat the question as one requiring 

 definite proof. 



A. G. Bourne, who also studied sections, agrees with Grati- 

 olet in almost every particular, and believes that the two 

 systems communicate by means of their finer branches ending 

 in capillary networks. But here again we miss the necessary 

 convincing evidence of the continuity. 



Since considerable doubt arose as to the correctness of the 

 generally accepted view, Mr. A. E. Shipley in 1888 re-investi- 

 gated the subject with the help of sections, and wrote a short 

 paper without figures in which he says (12), "A fragment of 

 the brown tissue of a leech shows at once the connection of the 

 lumen of the botryoidal tissue with that of the thin-walled 

 vessels. And my sections through Clepsine and Hirudo show 

 in numerous places the large openings by means of which the 

 botryoidal tissue is put into communication with the sinuses."^ 



1 In this work Gratiolet first showed the continuity of the botryoidal 

 channels with the vascular system (sinus or vessel), though the botryoidal 

 tissue was first correctly described and so named, by Lankester, and its con- 

 tinuity with capillaries and their mode of growth in connection with it 

 figured (8). 



2 A statement which it is difficult to reconcile with that found farther on, 

 that " certain large corpuscles which occur in the sinuses of Clepsine and 

 Pontobdella are not found in the blood-vessels, being ... too large to pass 

 through the communicating channels." As far as Clepsine is concerned, 

 Oka's results are, of course, directly opposed to those of Bourne and 

 Shipley. 



