REPORT ON THE SCHIZOPODA. 73 



of the trunk lie close together, at a considerable distance from the preceding ganglia, the 

 commissures being rather long, and also less distant, than are those connecting the 

 preceding ganglia. 



The supra-oesophageal or cerebral ganglion is rather large, and exhibits a somewhat 

 elliptical form, its transverse diameter lieing the larger. On its upper surface, 

 close to the anterior margin, is seen embedded the ocellus, or larval eye ; and 

 from each side proceed the greatly developed optic nerves, forming in the interior 

 of the eye-pedicles a large ganglionic tumescence, within which lies immersed the 

 previously mentioned luminous organ. Moreover, from the inferior face of the ganglion 

 originate two j^aii's of strong nervous trunks, each of which exhibits at the base a con- 

 spicuous ganglionic swelling ; the one pair passes anteriorly in a direct line to the 

 antenuula3, the other curves out exteriorly, entering the basal portion of the antennse. 

 The commissures connecting the cerebral ganglion with the first ventral are exceedingly 

 long and at a wide distance apart, encompassing the oesophagus, and are connected 

 together immediately behind it by a thin transverse commissure ; each, too, sends off 

 before its union with the mandibular ganglion a slender nerve, which passes apparently 

 to the stomach. 



The caudal ganglia are Ijy comparison exceedingly large, slightly exceeding even 

 those of the trunk, and are connected by very long commissures lying close together. 

 As is the case in Gnathophausia, and perhaps in most of the Podophthalmia, a paii" of 

 slender nerves, exclusive of the strong nerve-trunks originating from the ganglia them- 

 selves, extend from the commissures, apparently innervating the musculature of the tail. 

 Furthermore, from the last caudal ganglion originate numerous nerves, most of which 

 enter the caudal fan, innervating its various parts. 



Digestive System (see PL XI. fig. 5). — The oesophagus is very short, ascending per- 

 pendicularly to the stomach. Its walls would seem to Ije strongly chitinised, and are 

 continued into the inner (upper) coating of the anterior and posterior lips. The stomach 

 (st) lying, as usual, within the most anterior part of the visceral cavity in front of the 

 cervical groove, exhibits on the whole a similar structure to that in the Mysidae, 

 being armed, more particularly at the ventral face, with numerous chitinous ridges, beset 

 with delicate bristles. Several strong muscles are attached to the stomach, by means of 

 which its several parts admit of being moved one against the other, thus crushing or 

 bruising the food before it is forced into the intestine. The pyloric section of the stomach 

 has above two small, incurving caeca, and to its inferiorly protruding part is appended 

 the liver (l), in the form of two rather large ovoid masses, which are partly united, and 

 consist of a prodigious number of minute caeca, crowded together. The intestine {i) has 

 the form of an exceedingly narrow tube passing through the posterior part of the 

 trunk and the whole of tlie tail, and terminating in a short rectum that opens at the 

 base of the telsou through a longitudinal fissure. In the living animal the whole 



(ZOOL. CnALL. EXP. PART xxsvir. — 1885.) Oo 10 



