MR 



ON SOME LOWER ANN IDS. &***> 



surface of the pharynx often presents the appearance of a complicated net w ork of vessels 



formed by the breaking up of the principal vascular stems (figs. 17, IS); hut this is perhaps 

 due only to plication. 



The stomach is a large, somewhat square sac, often very Largely distended with food 

 and pressing against the body-wall; a few (apparently irregular) muscular septa j 

 from the body-wall to it. It is very largely moveable in a longitudinal dir< urn, hut 

 usually its posterior portion underlies the first pair of abdominal bristle-bundles. The 

 outer surface of the stomach and the intestine (which is quite similar to it, being merelj 

 separated by a constriction) is traversed by a series of < ipillary v Is, which are 

 difficult to detect and by no means so clear or definitely arranged in Ch. Urn i i 



the species figured by Leydig in his ' Lehrhuch.' They branch from tin main dorsal v< 

 and, like it, are surrounded and marked out by closely packed brownish ra miles, \\ 



8 in 



y in number in different individuals. Beneath these vessels and 



- 



f 



of large hexagonal flattened cells, whicb are ciliated and contain yellow gmnules. Tin 

 inner surface of the stomach and intestine is ciliated, the cilia bein < xtr< i ly line and 



quite invisible, except under the most favourable circumstances; for a long time they 



entirely escaped me (fig. 37). There is no differentiation of intestine or anus, sin 

 growth of zooids is continually proceeding behind, and what was the intestine < 

 individual becomes the stomach of another, but never the pharynx or « sophagus— tin 

 parts always being developed distinctly, from a deposit of homogeneous matter. 



J^erves.— The nervous system is a little difficult to make out Batisfi torilv; and in 

 Ch. limncei I have not observed what Leydig has put forward, with reference to tin 

 main trunks, in his drawings. It is easy to see, when a ventral vice, is tal n of tin 



under slight pressure, the infraoesophageal ganglion, its commissures | issin 



rr 



round the pharynx, and the longitudinal " cord" passing posteriorly and 



lobulated tissue on the surface of the pharynx, as in fig. 13. It » e*j I . tat* ti.» 



further over the pharyngeal bulb, where there is much of the lobd rtume; and the 



eord may be vaguely followed beyond this to another similar swelhng „■!„»,■ rtoMch. 



where it becomes lost by its own transparency and indefouten, -. 1 he « ■ , , m b 

 supraoesophageal ganglion, however, are more difficult to , sort** - a > ■ 



view of the worm is obtained, it may, with great care in fixing and , 1. n a 

 distinctly defined (figs. 14, 24). It is a broad band oi nerve- ..ssu,, w h , . U 

 the centre, and branching out into fine twigs in both on an.-r.or and porte, ,o, d, o 

 Leydig ha's figured a second ^pharyngeal £ •£—-£* ^ . 



with the infrapharyngeal mass, and apparently <*°^™*2mc». . x , , ,„,,,.,! 

 or the specialization of the pha^ g*£^j^ ^ ' ™* 



that such a structure does not exist m ^n 



for the difference. 



limncei, or the observations are ii 



Some four or five twigs pass 



It is either a specific distinction, or is due to the imm 



of Ch 



off from the suprapharyngcal ganglion to .he lip or 



* In the sexually mature specimens of Ch. hmnw 

 nerve-system is certainly as stated above ; but from I 

 Leydig's figure of that species. 



structures her. d re d are but r< iily mm. ft 



onfirm 



