24 Mr. P. H. Gosse on Asplanchna priodonta. 



ovaiy. To avoid confusion, the tortuous threads, with the tre- 

 mulous tags and the muscles, shown, are those of one side only. 

 6. Female : vertical aspect of the head. The upper side is the occiput, 

 where are seen the two incurved lobes, the small antennee, and 

 (more forward) the lateral eyes. In front are the two conical 

 masses, and between them, but on a lower level, the forceps- like 

 , jaws, with their cushion, pointing towards the phalangeal tube, 

 which is furnished with an eye near its margin. 



c. The jaws, seen vertically, under pressure. The delicate serratures on 

 "^i the edges, the two terminal points, and the accessory uncini are 



shown. 



d. The jaws seen laterally. The serratures are cut in the upper edge, which 



seems to project inwardly. The terminal points are unequal, the 

 i - upper being the longer. The uncini are attached to the lower 

 edge. 



e. Male : dorsal aspect. 



/. Idem: lateral aspect; right side. The globular organ near the lower 

 part is the sperm-sac, with a short bifid penis below it ; the pre- 

 putial sheath opens near the pointed extremity of the body. 

 Above the sperm-sac a granulated organ is seen extending from 

 it to the front of the head. Muscular threads, both longitudinal 



b&^oi'JiU ^^^ transverse, are seen, as is also one of the tortuous glands, like 

 a thickened cord. The phaiyngeal eye and one lateral eye are 

 represented. 



Plate II. 



h. Temale : left side. The head is retracted ; the crop is corrugated in its 

 '^'^^^ ordinary, condition of repose : the bladder is distended : there is a 



developing ovum in the ovisac, which has several conspicuous oil- 

 globules. One of the dorsal and one of the ventral orifices are 

 ;? ,^*i , ,: « well seen. Some of the organs represented in a. are not repeated 



i. ■ l^mkle : dorsal aspect. The head expanded ; the ciha rotating ; the 

 pharyngeal tube, with its eye, the jaws lying on their cushion, and 

 ■'.^.' .;^ , the crop beneath, are seen; below which is the long, tubular, very 

 i.sril^lJStf expansible stomach, wdth its two pancreatic glands, terminating 

 VTOjfi- ill ^ wide sacculate portion. (Perhaps the latter might be pro- 

 perly considered as an intestine.) On each side is the tortuous 

 gland, and the developing ovum is shown below all. The powerful 

 muscular bands that retract the head, the subordinate muscular 

 ■T' threads, and the transverse threads are well seen; as are the ex- 



tremely delicate floating filaments of nervous (?) matter, with their 

 numerous ganglia. 



P.S. Since the above was written, I had the pleasure of finding, 

 on the 30th of May, A. Brightwellii very numerous in several of 

 ihe little pools on Hampstead Heath. Volvox globator^ Bino- 

 charts tetractis, Anurcea serrulata, and other interesting forms 

 were found with them. The females of the Asplanchna were 

 much more numerous than the males, perhaps in the ratio of a 

 hundred to one. I gladly bear testimony to the accuracy of 

 Mr. Dalrymple^s anatomical figures of this species. — P. H. G. 



