574 TAUK SKOCiSHKlUi 



sonu'what iiUHlially on tlir olaw, coiitinup in most casi's right nut to tlic point of tlic daw and run 

 togetluT proxinially in most cases in tlic way sliown in fig. ."14 of Conchuecui siptnnctnca. Tiie 

 proximal ones of these secondary spines arc moderately strong or rather weak, the others 

 diminish gradually in size and strength tin' more distally tliey are situated. The lamellae are 

 often furnished with groups of rather short, rather soft or still hairs; on tlic other hand tlicrc 

 arc no spines and bristles at all. Behind the furcal claws there is often an unpaired, short-haired, 

 ratiicr weak, moderately Umg bristle. 



Alimentary organs:* — These are subject to only ratlicr slight variation in 

 this group. Contrary to the Cypridiniformes there is always a very well defined atri u in, which 

 is fairly well closed below, in front and at the back. This atrium is bounded at the back exclus- 

 ively l)v the somewhat rounded (when seen from l)(>]ow wedge-shaped; cf. fig. ']5 of Conchoecia 

 symmetrica in the present work) paragnates, which are always well developed. These have 

 on the ventral side some, in most cases four, rows of fine hairs running almost parallel to each 

 other and along the inner margin a row of hairs that are in most cases stiff and powerful. The 

 paragnates are attached on each side of the weakly arched imder lip. The upper lip is large 

 and helmet-shaped and is attached to the under lip by means of chitinous lists. Between the 

 upper lip and the paragnates there is on each side of the mouth a rather deep indentation; see 

 fig. 36 of Conchoecia symmetrica below; the pars incisiva of the coxale of the mandible 

 penetrates into this indentation; cf. G. W. MCller, 1894, pi. 1, figs. 18 and 19. The postero- 

 ventral part of the upper lip is somewhat lamellifoim; cf. G. W. MUlleh, 1894, pi. 37, 

 fig. 28; the rather strongly chitinized back edge of this part varies rather considerably in type in 

 the difierent genera, but is always furnished on both sides on the middle part with a row of more 

 or less powerful hairs. The inside of this part has at about the middle two transverse rows 

 of stiff and rather powerful hairs and groups of short and exceedingly fine hairs. On the ventral 

 side of the upper lip numerous unicellular glands emerge, the glands of the upper lip; cf. G. W. 

 MUller, 1894, pi. 37, fig. 28; in addition there is a gland, in most cases extensive, with its 

 exit in the atrium; cf. the figure just mentioned. The oesophagus is rather long, with strong 

 muscles, and is bent evenly and moderately strongly backwards; see G. W. MtJLLER, 1894, 

 pi. 35, fig. 16. The stomach is large, oval and is furnished on each side of the aperture of the 

 oesophagus with a rounded or rather elongated hepatic appendage, the lumen of which opens 

 into the stomach with a rather narrow canal. The rectum is very short and emerges in front 

 of the furca. No parts of the digestive organs ever penetrate between the lamellae of the shell. 



Sexual organs: — Male: — The testes are paired, consisting of two bag- 

 shaped oval bodies. From each of these there issues a rather short canal, the vas deferens, 

 which is verv much widened in mature specimens and which is often even more voluminous 

 than the testes; cf. G. W. MOller, 1894, pi. 38, fig. 19. The vasa deferentia are joined 

 inside the penis to an unpaired passage, which continues into the penis and emerges at its point. 

 Female: — The ovaries, like the testes, are paired and are situated posteriorly in the body ; 



* The description of these organs given in this work is for the most part taken from G. W. Muller's large mono- 

 graph, 1894 (pp. 119 and 120). This description, which seems to lie satisfactory in a treatment of the systematizatioii 

 of this group, must, however, be added to fairly considerably. I hope to have an opportunily of giving a detailed 

 description of the structure and mechanism of these organs in a subsequent work. 



