MR. F. D. DYSTER ON PHORONIS HIPPOCREPIA. 255 



ne renferme des Elements ' morphotiques ' quelconques, c'est-&,-dire des globules." And 

 Mr. Huxley* says, " it may be considered an established fact that, whatever the func- 

 tions of the varied vascular system and its contents in different classes of the Annuloida, 

 they have nothing to do with the blood or the blood-vessels. The latter are entirely 

 absent in the Annuloida at present known, the blood being simply contained in the peri- 

 visceral cavity and its processes." Nothing short of the most patient oliservation would 

 have induced me to state a fact which is incompatible with the opinions and observations 

 of Mr. Huxley and Milne-Edwards ; but while my own investigations leave no room for 

 doubt that the proper fluid of the vascular system in Fhoronis consists of a colour- 

 less liquor sanguinis densely crowded with red corpuscles, I am confirmed in the pro- 

 bability of the fact by the discovery of globules in the vascular system of Glycera by 

 M. de Quatrefages, against whose acciu-acy I do not think the sweeping statement of 

 Dr. "Williams is a suiiicient balance. Not only is it easy to define the vessels which con- 

 tain the corpuscles in the living worm, but I have several times, under the compressorium, 

 succeeded in isolating a capillary loop with its string of globules. 



There are one or two other points in which the Fhoronis deviates very remarkably from 

 the AnneKdan type. In the position of the anus at the anterior extremity in close proxi- 

 mity to the mouth, it stands, I believe, alone, though Mr. Busk has reminded me of the 

 analogy which this presents to the arrangement in Sipunculus, the annulose form of the 

 Echinoderms. The development of the nervous system is very small — ^indeed at present, 

 as before remarked, I cannot do more than guess at the presence of two oesophageal ganglia, 

 — whUe there is no trace of eye-spots, nor does the creature, like Serpula and Sabella, 

 exliibit any appearance of .sensibility to light. Negatively, Dr. Wright confirms this view 

 inasmuch as he makes no allusion to the nervous system, while Professor Allmant distinctly 

 says he could perceive none. In all the Capitibrauchiate Annelids the pharynx is short 

 and muscular, while in Fhoronis it is long and presents no appreciable trace of muscular 

 structure. In the same division, the alimentary tube has numerous dilatations corre- 

 sponding to the somites, while in Fhoronis it is a simple canal, and there exist neither 

 external segments nor internal septa, and there is no approach to pedal lobes, hooks, 

 pale£e or bristles. I believe that in Fhoronis there is no perivisceral cavity ; at all events, 

 there are no corpuscles such as are present in the perivisceral fluid of other AnneUda. 



I am indebted to my friend Mrs. Brett for the figui-es, which she has translated into 

 beauty from my rough diagrams, 



* Lectures on Natural History, Medical Gazette, vol. xxxiv. p. 385. 

 t Freshwater Polyzoa (Ray Society), p. 55. note. 



